NCERT Solutions Class 6 Science

Different examination boards including CBSE follow NCERT curriculum and structure in terms of concepts and answers, it is applicable across the board. Thus, it becomes important for the students to consider NCERT Science Class 6 at an initial stage of preparation for conceptual clarity. Then they must try and practise some questions and compare them with NCERT Solutions.

 

NCERT Class 6 Science Solutions 

Extramarks brings out the NCERT class 6 Science Solutions which is easy to access  and  understand as well. The solutions are provided by the subject matter experts who cross-check the answers so that students know how to write the answer to the questions in their upcoming examination irrespective of the board they follow. The NCERT solutions for class 6 science can be easily downloaded and accessed offline. 

 

NCERT Class 6 Science Chapter wise Solutions - 

Subject experts at Extramarks made sure that the answers must follow the recent NCERT curriculum and examination structure to maintain the authenticity and accuracy of the NCERT Solutions

 Here is the list of  NCERT solutions of class 6 Science chapters given below:  

  • Chapter 1: Food - Where Does it Come From?
  • Chapter 2 - Components of Food
  • Chapter 3 - Fibre to Fabric
  • Chapter 4 - Sorting Materials into Groups
  • Chapter 5 - Separation of Substances
  • Chapter 6 - Changes around Us
  • Chapter 7 - Getting to Know Plants
  • Chapter 8 - Body Movements
  • Chapter 10 - Motion and Measurement of Distances
  • Chapter 11 - Light, Shadows, and Reflections
  • Chapter 12 - Electricity and Circuits
  • Chapter 13 - Fun with Magnets
  • Chapter 14 - Water
  • Chapter 15 - Air Around Us
  • Chapter 16 - Garbage In, Garbage Out

 

NCERT Class 6 Science Chapter wise Solutions in Hindi Medium 

Extramarks has taken into consideration the problems that are faced by the Hindi medium students in getting solutions on the web, even if they find one, then they can’t trust on their reliability and accuracy. Extramarks bring out the same NCERT solutions for Class 6 Science in Hindi medium as well. The entire syllabus has been covered by NCERT Solutions with all the chapters mentioned above. Students just need to visit the Extramarks website to access it. 

 

Class 6 Science NCERT: An Overview of the Syllabus

Prior to NCERT solutions, brief conceptual notes are given to the students, so that they can get an overview of the chapters instead of jumping to the questions directly. A complete summary and keynotes are accessible on the Extramarks official website. 

 

Chapter 1: Food - Where Does it Come From?

Chapter 1 covers important concepts such as variety of food, food materials, parts of plant, and animal products as food. There are various in-text activities in the chapter to help students observe the food they eat on a daily basis, and their source of generation or production.

 

Chapter 2: Components of Food

The chapter teaches about various components of food such as minerals, proteins, and carbohydrates. Children will also learn about health benefits of these components, balanced diet and its importance, and other related topics.

 

Chapter 3: Fibre to Fabric

The chapter introduces students to different processes involved in making fabric from fibres. They will learn about production of clothes from different raw materials, the raw materials we get from plants, and animals, and the differences between natural and synthetic fibres.

 

Chapter 4: Sorting Materials into Groups

The chapter develops an understanding in students about categorising or sorting materials and objects based on their characteristics. Children will be taught to observe features like size, texture, shape etc. of the materials found in the surroundings.

 

Chapter 5: Separation of Substances

The chapter discusses different ways used to separate substances based on their original properties. These ways include churning, filtration, decantation etc. 

 

Chapter 6: Changes Around Us

The chapter helps students observe the changes that happen in the surrounding, and how and why they take place. Students will also be able to classify the changes as reversible and irreversible.

 

Chapter 7: Getting to Know Plants

There are various types of plants in the environment. Chapter 7 discusses some of these types of plants in detail. There are different activities in the chapter to introduce students to herbs, trees, shrubs etc. 

 

Chapter 8: Body Movements

The chapter covers different types of movements in the body. Students will learn about the parts that are involved in making our body move. The chapter also explains the types of joints and the types of movements they help our body perform.

 

Chapter 9: The Living Organisms and Their Surroundings

The chapter talks about the living organisms and surroundings they are found in. Students will also learn about the different types of environments where an organism can survive.

 

Chapter 10: Motion and Measurement of Distances

The chapter takes students through the phases of evolution of transport on the basis of understanding of motion. Students will learn about motion and its classifications. It will also talk about the methods and instruments used to measure distance between objects.

 

Chapter 11: Light, Shadows, and Reflections

The chapter covers light, shadows, and reflections in detail. Students will also get to know about other topics such as the objects that emit and do not emit light, their nature, properties and applications. 

 

Chapter 12: Electricity and Circuits

The chapter provides knowledge of concepts such as electrical devices, electricity, electric circuits, conductors, switches, and insulators. The other important topics covered are electric cells, connecting an electric cell to an electric bulb, attachments and terminals in an electric cell, and how to make an electric circuit.

 

Chapter 13: Fun with Magnets

In this chapter, students will learn about the discovery of magnets, classification of magnetic and non-magnetic materials, and applications of such materials.

 

Chapter 14: Water

The chapter talks about the necessity of water in lives, its conservation, misuse, and the various sources of water on Earth. Students will be made aware of the importance of saving water and preventing water pollution.

 

Chapter 15: Air Around Us

The chapter covers another important natural element, that’s air. Students will learn about the components of air and the role of the atmosphere. 

 

Chapter 16: Garbage In, Garbage Out

The chapter introduces students to the basic level of waste management. It covers topics like dealing with garbage, recycling paper and plastic, vermicomposting, etc. 

 

NCERT Solutions for Class 6 Science Marks Weightage 

 NCERT Solutions for Class 6 include all of the fundamentals of science for CBSE exams.  Class 6 Science final examination is 100 marks. The NCERT Class 6 Science Solutions include the complete chapters as per the curriculum.

 

Benefits of NCERT Solutions Science Class 6

- The advantage of preparing through NCERT Solutions are as follows:

  • The NCERT Solutions offer a thorough understanding of each and every chapter.
  • The explanations are written in a simple and clear language so that all students can easily understand and benefit from them.
  • The solutions are curated by teachers who are considered to be subject matter experts.
  • The answers also provide practical examples so that students can learn through real life experiences and help them develop critical thinking skills.
  • All possible topics that may be covered in the question papers and tests are addressed in the solutions, allowing students to score well in the exams.
  • The solutions are written in a clear, simple and engaging manner to assist students to earn the highest possible score and continue to reap the benefits in the subsequent classes as well. 

 

Why should you choose Extramarks?

Extramarks prepare solutions for various boards such as CBSE,  ICSE, and NCERT  in accordance with the latest guidelines in a clear and crystal manner. . Extramarks subject experts cross-check the answer with NCERT concepts before sharing it on board. . Students can easily rely on the NCERT solutions given by Extramarks in terms of accuracy and methodology that has been opted for writing the answer (with following the time constraint as per the question). 

Extramarks make learning content with the goal of assisting students in grasping the fundamental principles in every chapter along with the topic in a systematic manner rather than just memorising it. When students comprehend the concepts well, they will be able to answer any question. . Having a  thorough knowledge of the principles also aids in their application in real-life situations. In-depth knowledge and a solid foundation will help you do well in school, as well as in many competitive examinations. 

Students who use Extramarks study material may study and prepare for their examinations without having to worry about getting the right study material, and they can save time for extra practice before their tests. The content provided by Extramarks allows students to assess, revise their syllabus and clarify their doubts if any way ahead of exams.

Q.1 Fill in the blanks in the following

(i) Artificial magnets are made in different shapes such as __________, __________ and ____________.

(ii) The Materials which are attracted towards a magnet are called ________.

(iii) Paper is not a ______ material.

(iv) In olden days, sailors used to find direction by suspending a piece of ___________.

(v) A magnet always has __________ poles.

Ans

(i) Artificial magnets are made in different shapes such as bar magnets, horse-shoe magnets, and cylindrical magnets.

(ii) Materials which are attracted towards magnets are called magnetic materials.

(iii) Paper is not a magnetic material.

(iv) In olden days, sailors used to find direction by suspending a piece of bar magnet.

Explanation: The sailors used to find direction by suspending a piece of bar magnet because a freely suspended magnet always comes to rest in the North-South direction.

(v) A magnet always has two poles.

Explanation: A magnet consists two poles namely the South pole (S) and the North pole (N).

Q.2 State whether the following statements are true or false:

(i) A cylindrical magnet has only one pole.

(ii) Artificial magnets were discovered in Greece.

(iii) Similar poles of a magnet repel each other.

(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them.

(v) Bar magnets always point towards North-South direction.

(vi) A compass can be used to find East-West direction at any place.

(vii) Rubber is a magnetic material.

Ans

(i) A cylindrical magnet has only one pole. (False)

Explanation: A magnet cannot exist with a single pole. A magnet always exists with two poles. Hence, a cylindrical magnet has also two poles.

(ii) Artificial magnets were discovered in Greece. (False)

(iii) Similar poles of a magnet repel each other. (True)

Explanation: Like poles of magnets repel each other, while unlike poles of magnets attract each other.

(iv) Maximum iron filings stick in the middle of a bar magnet when it is bought near them. (False)

Explanation: The magnetic strength of a bar magnet is maximum at its two poles and minimum at middle. Hence, maximum iron filings will stick at two ends of the magnet and minimum in the middle.

(v) Bar magnets always point towards the North−South direction. (True)

(vi) A compass can be used to find the East−West direction at any place. (True)

Explanation: We know that a magnetic compass always points towards the North−South direction. If the North−South direction is known, then the East−West direction can be found.

(vii) Rubber is a magnetic material. (False)

Explanation: Rubber is a non-magnetic material as it is not attracted by a magnet.

Q.3 It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it.

Ans

In a pencil sharpener, the blade is made of iron and iron is a magnetic material. Magnets have tendency to attract the objects made of iron. Hence, a pencil sharpener gets attracted towards both the poles of a magnet.

Q.4 Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.

Column I

Column II

N-N

_______

N- ___

Attraction

S-N

_______

__- S

Repulsion

Ans

Column I

Column II

N-N

Repulsion

N-S

Attraction

S-N

Attraction

S-S Repulsion

Q.5 Write any two properties of a magnet.

Ans

Two properties of a magnet are:

i. Unlike poles of two magnets attract each other.

ii. Like poles of two magnets repel each other.

Q.6 Where are poles of a bar magnet located?

Ans

There are two poles of a magnet namely North pole and South pole. They are located at the two ends of the magnet.

Q.7 A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?

Ans

The poles of a bar magnet with no marking can be identified by suspending the bar magnet freely with the help of a light thread. A freely suspended bar magnet always comes to rest in the North−South direction.The north facing end of the magnet indicates its north pole while the south facing end indicates its south pole.

Q.8 You are given an iron strip. How will you make it into a magnet?

Ans

To convert an iron strip into a magnet, place the iron strip on the table. Now, rub a permanent magnet on the strip. While doing this, the movement of your hand should always be in the same direction. After doing this 40–50 times, the iron piece would attain magnetic properties.

Q.9 How is a compass used to find directions?

Ans

A compass has a magnetic needle which can move around a pivot. As a magnet always stays in north-south direction hence, this property of magnet is used to find the directions with the help of a compass.

Q.10 A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Affect observed in each case is stated in Column I. Possible reasons for the observed affects are mentioned in Column II. Match the statements given in Column I with those in Column II.

Column I

Column II

Boat gets attracted towards the magnet Boat is fitted with a magnet with the north pole towards its head
Boat is not affected by the magnet Boat is fitted with a magnet with the south pole towards its head
Boat moves towards the magnet when the north pole of the magnet is brought near its head Boat has a small magnet fixed along its length
Boat moves away from the magnet when the north pole is brought near its head Boat is made of magnetic material
Boat floats without changing its direction Boat is made of a non-magnetic material

Ans

Column I Column II
Boat gets attracted towards the magnet Boat is made of magnetic material
Boat is not affected by the magnet Boat is made of a non-magnetic material
Boat moves towards the magnet when the north pole of the magnet is brought near its head Boat is fitted with a magnet with the south pole towards its head
Boat moves away from the magnet when the north pole is brought near its head Boat is fitted with a magnet with the north pole towards its head
Boat floats without changing its direction Boat has a small magnet fixed along its length

Q.11 Fill in the blanks:

(a) A device that is used to break an electric circuit is called _____.

(b) An electric cell has _____ terminals.

Ans

(a) A device that is used to break an electric circuit is called a switch.

(b) An electric cell has two terminals.

Q.12 Mark ‘True’ or ‘False’ for the following statements:

(a) Electric current can flow through metals.

(b) Instead of metal wires, a jute string can be used to make a circuit.

(c) Electric current can pass through a sheet of thermo Col.

Ans

(a) Electric current can flow through metals. (True)

Explanation: Electric current can pass through metals as they allow an electric current to flow through them easily.

(b) Instead of metal wires, a jute string can be used to make a circuit. (False)

Explanation: Jute string is an insulator. Hence, electric current cannot pass through it.

(c) Electric current can pass through a sheet of thermo Col. (False)

Explanation: Thermo Col is also an insulator. Hence, electric current cannot pass through it.

Q.13 Explain why the bulb would not glow in the arrangement shown in Fig.12.13.

Ans

In the given circuit, a tester holder is connected in series. Electric current cannot pass through tester holders because it is a bad conductor of electricity. Hence, the current will not flow through the circuit and hence, the bulb will not glow.

Q.14 Complete the drawing shown in Fig 12.14 to indicate where the free ends of the two wires should be joined to make the bulb glow.

Ans

In order to complete the circuit, the positive terminal of the cell should be connected to one end of the bulb, and the other terminal of the bulb should be connected to the other end of the bulb. It can be shown in the figure.

Q.15 What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.

Ans

A switch is used to complete or break an electric circuit. If the switch is ‘ON’, then current will flow through the circuit. On the other hand, if the switch is ‘OFF’, then current will not flow through the circuit. Electric fans, electric lamps, washing machines, juicers and mixers, etc. have switches built into them.

Q.16 Would the bulb glow after completing the circuit shown in Fig. 12.14, if we use an eraser instead of a safety pin?

Ans

No. The bulb will not glow if we connect an eraser in the circuit. It is because erasers are bad conductor of electricity. They do not conduct electricity. The circuit becomes an open circuit.

Q.17 Would the bulb glow in the circuit shown in Fig. 12.15?

Ans

No. The bulb will not glow because the two terminals of the cell are connected to the single terminal of the bulb. In order to complete the circuit, the two terminals of the cell should be connected to the two terminals of the bulb.

Q.18 Using the “conduction tester” on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.

Ans

The bulb of the conduction tester glows when the tester is touched with the object. It shows that the given object conducts electricity. Hence, the object is a conductor in nature.

Q.19 Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.

Ans

An electric switch conducts electricity through its internal parts and one may get an electric shock if it is touched with naked hands. Hence, it should be touched with rubber gloves in hand because rubber cannot conduct electricity.

Q.20 The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?

Ans

Plastics and rubbers are the bad conductor of electricity. So, handle of tools such as screwdrivers, pliers, etc. which are used by electricians to repair electrical appliances usually have plastic or rubber cover on them.

Q.21 Rearrange the boxes given below to make a sentence that helps us understand opaque objects.

Ans

It would be “Opaque objects make shadows”.

Q.22 Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:

Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the flame of a gas burner, a sheet of cardboard, a lighted torch, a sheet of cellophane, a wire mesh, kerosene stove, sun, firefly, moon.

Ans

Object

Transparent
/Translucent
/Opaque

Luminous/Non-luminous

Air

Transparent

Non-luminous

Water

Transparent

Non-luminous

Piece of rock

Opaque

Non-luminous

Sheet of aluminum

Opaque

Non-luminous

Mirror

Opaque

Non-luminous

Wooden Board

Opaque

Non-luminous

Sheet of polythene

Translucent

Non-luminous

CD

Translucent

Non-luminous

Smoke

Translucent

Non-luminous

Sheet of plane glass

Translucent

Non-luminous

Fog

Translucent

Non-luminous

Piece of red hot iron

Opaque

Luminous

Umbrella

Opaque

Non-luminous

Lighted fluorescent tube

Opaque

Luminous

Wall

Opaque

Non-luminous

Sheet of carbon paper

Opaque

Non-luminous

Flame of a gas burner

Translucent

Luminous

Sheet of cardboard

Opaque

Non-luminous

Lighted torch

Opaque

Luminous

Sheet of cell phone

Translucent

Non-luminous

Wire mess

Translucent

Non-luminous

Kerosene stove

Opaque

Luminous

Sun

Opaque

Luminous

Firefly

Opaque

Luminous

Moon

Opaque

Non-luminous

Q.23 Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?

Ans


A cylinder kept in sunlight can form a circular shadow or a rectangular shadow. It can be obtained depending on its orientation related to the Sun. The cylinder forms a circular shadow when its top faces the Sun. When the side of the cylinder faces the Sun, then it forms rectangular shadow.

Q.24 In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?

Ans

In a completely dark room, there will be no light. The formation of an image depends upon the reflection of light. Therefore, no reflection of light takes place by the mirror placed in the dark room. Hence, no image will get formed by a mirror in a completely dark room.

Q.25 Give two examples each, of modes of transport used on land, water and air

Ans

Modes of transport used on land: Cars and trains

Modes of transport used on water: Ships and boats

Modes of transport used in air: Airplanes and helicopters

Q.26 Fill in the blanks:

(i) One metre is ______________ cm.

(ii) Five kilometre is ______________ m.

(iii)Motion of a child on a swing is ______________.

(iv) Motion of the needle of a sewing machine is ______________.

(v) Motion of wheel of a bicycle is______________.

Ans

(i) One metre is 100 cm.

Explanation: There are 100 cm in 1 m.

(ii) Five kilometres is 5000 m.

Explanation: There are 1000 m in 1 km.

So, 5 km = 5 × 1000 m = 5000 m

(iii) Motion of a child on a swing is periodic.

Explanation: At a certain time interval, the motion of a swing repeats itself. Hence, it is an example of periodic motion.

(iv) Motion of the needle of a sewing machine is periodic.

Explanation: The needle of a sewing machine moves up and down frequently in a certain time interval. So, it is an example of periodic motion.

(v) Motion of the wheel of a bicycle is circular.

Explanation: The wheel of a bicycle rotates about a fixed point as the bicycle moves. Thus, it is an example of circular motion.

Q.27 Why can a pace or a footstep not be used as a standard unit of length?

Ans

The size of the foot is not same of each person. When footsteps of two people are used to measure the length, the two distances may not be equal. Therefore, footstep is not a constant quantity and cannot be used as a standard unit of length.

Q.28 Arrange the following lengths in their increasing magnitude:

1 metre, 1 centimetre, 1 kilometre,1 millimetre.

Ans

On converting all the given measures in millimetres (mm), we get

1 cm = 10 mm

1 m = 100 cm = 1000 mm

1 km = 1000 m = 100000 cm = 1000000 mm

So, the lengths in increasing order of magnitude can be written as,

1 millimetre < 1 centimetre < 1 metre < 1 kilometre

Q.29 The height of a person is 1.65 m. Express this in cm and mm.

Ans

Given, height of the person = 1.65 m

As, 100 cm = 1 m

So, height of the person in cm = 1.65 × 100 cm = 165 cm

Also, 1000 mm = 1 m

So, height of the person in mm = 1.65 × 1000 cm = 1650 mm

Q.30 The distance between Radha’s home and her school is 3250 m. Express this distance into km.

Ans

Given, the distance between Radha’s home and her school = 3250 m As 1 km = 1000 m or 1 m = 1 1000 km Converting 3250 m into km, we get 3250 m = 3250× 1 1000 km = 3.25 km MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVv0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=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@BBA0@

Q.31 While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle?

Ans

Given, reading at one end = 3.0 cm

reading at the other end = 33.1 cm

The length of the knitting needle can be calculated by subtracting 33.1 cm by 3.0 cm.

length of the knitting needle = 33.1 cm – 3.0 cm = 30.1 cm

Hence, the length of the knitting needle would be 30.1 cm.

Q.32 Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.

Ans

Similarities: The blades of the fan and the wheels of the bicycle are attached at a fixed point. Secondly, both have circular motion about their respective fixed points.

Differences: The blades of the fan have circular motion while the bicycle has linear motion. Secondly, the motion of the blades of a fan is periodic while the motion of a bicycle is rectilinear motion.

Q.33 Why would you not like to use a measuring tape made of an elastic material like rubber to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with such a tape?

Ans

An elastic measuring tape is not a suitable measuring scale because it can be stretched. In this case, the measured length would not be correct. If you measure the length of an object twice using an elastic tape, then you may get different values of the same length.

Q.34 Give two examples of periodic motion.

Ans

  1. In a simple pendulum, the bob repeats its motion at a certain time interval. This motion is known as periodic motion.
  2. The motion of a swing repeats its motion at a certain time interval. Thus, a girl sitting on a swing has periodic motion.

Q.35 What is the composition of air?

Ans

Air is a mixture of nitrogen, oxygen, small amount of carbon dioxide, water vapour and some other gases. Nitrogen constitutes 78% of the air. Oxygen constitutes 21% of the air. Carbon dioxide, water vapour and other gases constitute only 1% of the air.

Q.36 Which gas in the atmosphere is essential for respiration?

Ans

Oxygen is essential for respiration.

Q.37 How will you prove that air supports burning?

Ans

To prove that air supports burning, we will perform an activity.

To perform this activity, things required are candle, water, container and matchbox.

First of all take a container and fix a candle in the middle of the container. Fill the container with some water. Now, light the candle and then cover it with an inverted container.

After some time, it is observed that candle extinguishes.

Candle extinguishes because the amount of air is limited inside the inverted container. Hence, supply of oxygen is also limited.

Once oxygen is completely consumed, the candle blows off. This proves that oxygen is essential for burning.

Q.38 How will you show that air is dissolved in water?

Ans

To show that air is dissolved in water, take some water in a pan and heat it slowly. Just before the water begins to boil, look carefully at the bottom of the pan. Tiny air bubbles are seen at the bottom of the pan before the water actually boils. These air bubbles come from the air dissolved in water. When we heat the water, air dissolved in it escapes.

Q.39 Why does a lump of cotton wool shrink in water?

Ans

A lump of cotton wool shrinks in water because when it is immersed in water, air present in it escapes and it reduces in size.

Q.40 The layer of air around the earth is known as ______.

Ans

The layer of air around the earth is known as atmosphere.

Q.41 The component of air used by green plants to make their food, is ___________.

Ans

The component of air used by green plants to make their food, is carbon dioxide.

Q.42 List five activities that are possible due to the presence of air.

Ans

Activities that are possible due to the presence of air are:

  1. Photosynthesis
  2. Respiration
  3. Flight of birds, bats and insects
  4. Movement of sailing yachts, gliders, parachutes and aeroplanes
  5. Generation of electricity by windmill

Q.43 How do plants and animals help each other in the exchange of gases in the atmosphere?

Ans

During photosynthesis plants take carbon dioxide from atmosphere and make their own food and oxygen is produced in this process. Plants also consume oxygen during respiration but amount of oxygen released during photosynthesis is more than the amount of oxygen used during respiration. Animals inhale oxygen produced by plants and in turn, carbon dioxide is produced.

In this way, plants and animals help each other in the exchange of gases in the atmosphere.

Q.44 Fill up the blanks in the following:

(a) The process of changing of water into its vapour is called _________.

(b) The process of changing water vapour into water is called _________.

(c) No rainfall for a year or more may lead to ________ in that region.

(d) Excessive rains may cause _________.

Ans

(a) The process of changing of water into its vapour is called evaporation.

(b) The process of changing water vapour into water is called condensation.

(c) No rainfall for a year or more may lead to drought in that region.

(d) Excessive rains may cause flood.

Q.45 State for each of the following whether it is due to evaporation or condensation:

(a) Water drops appear on the outer surface of a glass containing cold water.

(b) Steam rising from wet clothes while they are ironed.

(c) Fog appearing on a cold winter morning.

(d) Blackboard dries up after wiping it.

(e) Steam rising from a hot girdle when water is sprinkled on it.

Ans

(a) Water drops appear on the outer surface of a glass containing cold water. (Condensation)

(b) Steam rising from wet clothes while they are ironed. (Evaporation)

(c) Fog appearing on a cold winter morning. (Condensation)

(d) Blackboard dries up after wiping it. (Evaporation)

(e) Steam rising from a hot girdle when water is sprinkled on it. (Evaporation)

Q.46 Which of the following statements are “true”?

(a) Water vapour is present in air only during the monsoon. ( )

(b) Water evaporates into air from oceans, rivers, and lakes but not from the soil. ( )

(c) The process of water changing into its vapour, is called evaporation. ( )

(d) The evaporation of water takes place only in sunlight. ( )

(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler. ( )

Ans

(a) Water vapour is present in air only during the monsoon. (False)

(b) Water evaporates into air from oceans, rivers, and lakes but not from the soil. (False)

(c) The process of water changing into its vapour, is called evaporation. (True)

(d) The evaporation of water takes place only in sunlight. ( False)

(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler. (True)

Q.47 Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help? If yes, how?

Ans

Yes, spreading of school uniform near an anghiti or heater would help to dry it quickly. Heat generated from anghiti or heater will warm up the surroundings. Water evaporates at faster rate in warm surroundings. Therefore, school uniform will dry up quickly by spreading it near an anghiti.

Q.48 Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you notice a puddle of water around it. Why?

Ans

Puddle of water is observed due to condensation of water vapours present in air around the surface of bottle.The water vapours present around the surface of the bottle touch the ice-cold surface of the bottle and get converted to water droplets.

Q.49 To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet.

Ans

When we breathe out, water vapours along with carbon dioxide are released. If we breathe out on glasses, the released water vapours collide with surface of the glass and condense, thereby making it wet.

Q.50 How are clouds formed?

Ans

Water from water bodies and plants is transferred to air through evaporation and transpiration. When the air (laden with water vapours) moves up, it gets cooler and cooler. At sufficient heights, the air becomes so cool that the water vapour present in it condenses to form tiny drops of water called droplets. These tiny droplets remain floating in air and appear to us as clouds.

Q.51 When does a drought occur?

Ans

Drought occurs when there is insufficient or no rain in a region for a long time. The soil continues to lose water by evaporation and transpiration. Since it is not being brought back by rain, the soil becomes dry. The level of water in ponds and wells of the region goes down and some of them even dry up. The level of ground water also goes down. These conditions lead to drought.

Q.52 To walk through a water logged area, you usually shorten the length of your dress by folding it. Can this change be reversed?

Ans

Yes, the length of dress can again be increased by unfolding it. Therefore, it is a reversible change.

Q.53 You accidentally dropped your favourite toy and broke it. This is change you did not want. Can this change be reversed?

Ans

No, this change cannot be reversed.

Q.54 Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.

S.No. Change Can be reversed(Yes/No)
1. The sawing of a piece of wood
2. The melting of ice candy
3. Dissolving sugar in water
4. The cooking of food
5. The ripening of a mango
6. Souring of milk

Ans

S.No. Change Can be reversed(Yes/No)
1. The sawing of piece of wood No
2. The melting of ice candy Yes
3. Dissolving sugar in water Yes
4. The cooking of food No
5. The ripening of a mango No
6. Souring of milk No

Q.55 A drawing sheet changes when you draw a picture on it. Can you reverse this change?

Ans

If we draw a picture on a drawing sheet with a pencil, then the picture can be erased with an eraser. Therefore, we can get back the original drawing sheet.

If we draw a picture on a drawing sheet with a pen, then the original drawing sheet cannot be obtained as we cannot erase ink.

Q.56 Give examples to explain the differences between changes that can or cannot be reversed.

Ans

1. Formation of curd from milk is an irreversible change as a new product (curd) is formed. Neither any bacteria nor any change in conditions can convert curd back into milk.

2. Take a piece of paper and fold it to make a toy aeroplane. We can get back the original piece of paper by unfolding it. Take the same piece of paper and draw an aeroplane on it, cut along its outline. In this condition we cannot get back the original piece of paper as pieces of paper cannot be rejoined.

3. Take some dough and make a ball. Try to roll out a chapati. After we roll out a chapati from a ball of dough, the chapati can be converted back to ball. Once we cook the chapati, it cannot be converted back to ball.

Q.57 A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?

Ans

No, the change in POP cannot be reversed. Plaster of Paris (POP) has a property of setting into a hard mass on wetting with water due to the formation of a new compound called gypsum. Once the POP changes to gypsum, it cannot be converted back into POP. Hence, it is an irreversible change.

Q.58 A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?

Ans

Cement sets into a hard mass on mixing with water. The hard mass obtained cannot be converted back to cement. Therefore, it is essential to keep cement away from rain, otherwise it will change into a hard mass which is of no use.

Q.59 Why do we need to separate different components of a mixture? Give two examples.

Ans

Different components of a mixture are separated either to separate undesired components, impurities or to obtain more than one useful components from the mixture.

Examples:

1) Small stone pieces and unwanted seed grains are removed from rice or dal before cooking.

2) From petroleum useful components like petrol, diesel kerosene, etc. are separated.

Q.60 What is winnowing? Where is it used?

Ans

Winnowing is a process of separating heavier and lighter components of a mixture by wind or by blowing air. This method is based on the property that grains are heavier than husk and hay.

Farmers use this method to separate grains from husk and hay.

Q.61 How will you separate husk or dirt particles from a given sample of pulses before cooking?

Ans

Husk or dirt particles from the given sample of pulses can be separated by sedimentation. In this process, water is added to the pulses. Pulses being heavier settle down at the bottom and the impurities like husk and dust particles go into water. Water along with dust particles is removed by the process of decantation, leaving the pulses at the bottom.

Q.62 What is sieving? Where is it used?

Ans

Sieving is the process of separating solid components of a mixture varying in size. In this process, sieves with holes of proper size is used. Sieving allows the fine particles to pass through the holes of sieves, leaving behind the bigger particles on the sieve.

Husk and stones from wheat are separated by sieving.

Q.63 How will you separate sand and water from their mixture?

Ans

Mixture of sand and water can be separated by two methods:

1) Combination of sedimentation and decantation

2) Filtration

1) Combination of sedimentation and decantation: Take the mixture of sand and water in a container and allow the mixture to stand for some time. Sand particles being heavier settle down at the bottom. This process is called sedimentation. Water is poured out into another container without disturbing sand. This process is called decantation.

2) Filtration: Mixture of sand and water is allowed to pass through a strainer or muslin cloth. Water goes through strainer and sand remains on the strainer.

Q.64 Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?

Ans

Yes, it is possible to separate sugar from wheat flour. Mixture of sugar and wheat flour is allowed to pass through sieve. Wheat flour particles being fine pass through the holes of sieve and sugar remains on the sieve.

Q.65 How would you obtain clear water from a sample of muddy water?

Ans

Clear water from the sample of muddy water can be obtained by the process of filtration. Muddy water is allowed to pass through muslin cloth or filter paper. Water passes through the muslin cloth and mud particles remain on the muslin cloth.

Q.66 Fill up the blanks

(a) The method of separating seeds of paddy from its stalks is called ________.

(b) When milk, cooled after boiling, is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of _________.

(c) Salt is obtained from seawater by the process of _______.

(d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clear water was then poured off the top. The process of separation used in this example is called ________.

Ans

(a) The method of separating seeds of paddy from its stalks is called threshing.

(b) When milk, cooled after boiling, is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of filtration.

(c) Salt is obtained from seawater by the process of evaporation.

(d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clear water was then poured off the top. The process of separation used in this example is called decantation.

Q.67 True or false?

(a) A mixture of milk and water can be separated by filtration.

(b) A mixture of powdered salt and sugar can be separated by the process of winnowing.

(c) Separation of sugar from tea can be done with filtration.

(d) Grain and husk can be separated with the process of decantation.

Ans

(a) A mixture of milk and water can be separated by filtration. (False)

(b) A mixture of powdered salt and sugar can be separated by the process of winnowing. (False)

(c) Separation sugar from tea can be done with filtration. (False)

(d) Grain and husk can be separated with the process of decantation. (False)

Q.68 Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add ice to the lemonade before or after dissolving sugar? In which case would it be possible to dissolve more sugar?

Ans

We should add ice to the lemonade after dissolving sugar.

More sugar can be dissolved before adding ice to the lemonade. This is because sugar dissolves very slowly in cold water.

Q.69 Name five objects which can be made from wood.

Ans

Objects made from wood are:

  1. Chair
  2. Table
  3. Wardrobe
  4. Drum sticks
  5. Doors

Q.70 Select those objects from the following which shine:

Glass bowl, plastic toy, steel spoon, cotton shirt

Ans

Glass bowl, Steel spoon

Q.71 Match the objects given below with the materials from which they could be made. Remember, an object could be made from more than one material and a given material could be used for making many objects.

Objects Materials
Book Glass
Tumbler Wood
Chair Paper
Toy Leather
Shoes Plastics

Ans

Objects Materials
Book Paper
Tumbler Glass, plastics
Chair Wood, plastics
Toy Plastics, wood
Shoes Leather

Q.72 State whether the statements given below are True or False.

(i) Stone is transparent, while glass is opaque.

(ii) A notebook has lustre while eraser does not.

(iii) Chalk dissolves in water.

(iv) A piece of wood floats on water.

(v) Sugar does not dissolve in water.

(vi) Oil mixes with water.

(vii) Sand settles down in water.

(viii) Vinegar dissolves in water.

Ans

(i) Stone is transparent, while glass is opaque. (False)

(ii) A notebook has lustre while eraser does not. (False)

(iii) Chalk dissolves in water. (False)

(iv) A piece of wood floats on water. (True)

(v) Sugar does not dissolve in water. (False)

(vi) Oil mixes with water. (False)

(vii) Sand settles down in water. (True)

(viii) Vinegar dissolves in water. (True)

Q.73 Given below are the names of some objects and materials:

Water, basket ball, orange, sugar, globe, apple and earthen pitcher

Group them as:

(a) Round shaped and other shapes

(b) Eatables and non eatables

Ans

Round Shaped Other Shapes
Basket ball Water
Orange Sugar
Globe
Apple
Earthen pitcher
Eatables Non eatables
Orange Basket ball
Apple Globe
Water Earthen pitcher
Sugar

Q.74 List all the items known to you that float on water. Check and see if they will float on an oil or kerosene.

Ans

Some of the items that will float on water are listed below:

  1. Plastic bottle
  2. Pencil
  3. A piece of paper
  4. A log of wood
  5. A piece of thermocol
  6. Cork
  7. Plastic ball
  8. Balloons

A few of these like balloons can float on kerosene or oil. This is because density of balloon is less than oil or kerosene.

Q.75 Find the odd one out from the following:

a) Chair, Bed, Table, Baby, Cupboard

b) Rose, Jasmine, Boat, Marigold, Lotus

c) Aluminium, Iron, Copper, Silver, Sand

d) Sugar, Salt, Sand, Copper sulphate

Ans

a) Baby (others are made up of wood)

b) Boat (rest are flowers)

c) Sand (rest are metals)

d) Sand (others are soluble in water)

Q.76 Classify the following fibres as natural or synthetic:

nylon, wool, cotton, silk, polyester, jute

Ans

Natural Fibre Synthetic Fibre
Wool Nylon
Cotton Polyester
Silk
Jute

Q.77 State whether the following statements are true or false:

a) Yarn is made from fibres.

b) Spinning is a process of making fibres.

c) Jute is the outer covering of coconut.

d) The process of removing seed from cotton is called ginning.

e) Weaving of yarn makes a piece of fabric.

f) Silk fibre is obtained from the stem of a plant.

g) Polyester is a natural fibre.

Ans

a) Yarn is made from fibres. (True)

b) Spinning is a process of making fibres. (False)

c) Jute is the outer covering of coconut. (False)

d) The process of removing seed from cotton is called ginning. (True)

e) Weaving of yarn makes a piece of fabric. (True)

f) Silk fibre is obtained from the stem of a plant. (False)

g) Polyester is a natural fibre. (False)

Q.78 Fill in the blanks:

a) Plant fibres are obtained from ______ and _______.

b) Animals fibres are ______ and ______.

Ans

a) Plant fibres are obtained from fruits and stems.

b) Animals fibres are wool and silk.

Q.79 From which parts of the plant, cotton and jute are obtained?

Ans

Cotton fibres are obtained from the fruits of the cotton plant. Fruits of cotton plant are called cotton bolls.Jute fibre is obtained from the stem of the jute plant.

Q.80 Name two items that are made from coconut fibre.

Ans

Two items that are made from coconut fibres are:

(1) Floor mats

(2) Ropes

Q.81 Explain the process of making yarn from fibre.

Ans

The process of making yarn from fibres is called spinning.In this process, fibres are drawn out and twisted.This brings the fibres together to form a yarn. Spinning is done by hand spindles (Takli or Charkha) or spinning machines.

Q.82 (a) Which kind of garbage is not converted into compost by the redworms?
(b) Have you seen any other organism besides redworms, in your pit? If yes, try to find out their names. Draw picture of these.

Ans

(a) The garbage that contains plastic bags, metal or plastic cans, broken glass pieces, aluminum foil is not converted into compost by redworms.
(b) Besides redworms, other organisms such as flies, spiders, cockroaches, maggots, flies, small insects etc. can also be observed in the pit.

Q.83 Discuss:
(a) Is garbage disposal the responsibility only of the government?
(b) Is it possible to reduce the problems relating to disposal of garbage?

Ans

(a) Proper disposal of garbage should be a responsibility of every citizen. Every citizen should put his efforts to reduce the generation of waste. It is a responsibility of every individual to throw the garbage properly in bins. Municipalities have provided two types of bins for waste disposal. Blue coloured bin is for the wastes that can be reused, such as glass, metals and plastics. Green coloured bin is for the collection of kitchen wastes and other animal or plant wastes. It is our responsibility to throw the waste in the bin specified for the type of waste so that it would be easy for municipality to finally dispose off the waste.

(b) Yes, it is possible to reduce the problems relating to disposal of garbage. Following steps can be taken to reduce the problems relating to disposal of garbage:
1. One should use more of paper bags, cloth bags or jute bags while shopping.
2. One should use separate bins for recyclable or non-recyclable wastes.
3. Compost should be prepared from the kitchen waste.
4. General awareness programs should be run to make people aware about the bad effects of improper disposal of waste.

Q.84 (a) What do you do with the left over food at home?
(b) If you and your friends are given the choice of eating in a plastic plate or a banana leaf platter at a party, which one would you prefer and why?

Ans

(a) Left over food can be utilised in following ways:

1. Left over food at home can be used to make some other items and then can be consumed.

2. If it cannot be used in this way, then it should be collected and distributed to the poor people.

3. If the left over food has spoiled, then it should be collected and dumped into soil to make compost.

(b) One should choose eating in a banana leaf platter because of the following reasons:

1. They are easy to dispose.

2. They are eco-friendly.

Q.85 (a) Collect pieces of different kinds of paper. Find out which of these can be recycled.
(b) With the help of a lens look at the pieces of paper you collected for the above question. Do you see any difference in the material of recycled paper and a new sheet of paper?

Ans

(a) All the pieces of different kinds of paper can be recycled.
(b) In comparison with the new sheet of paper, the recycled paper is of poor quality, dull in colour and rough in texture.

Q.86 (a) Collect different kinds of packaging material. What was the purpose for which each one was used? Discuss in groups.
(b) Give an example in which packaging could have been reduced?
(c) Write a story on how packaging increases the amount of garbage.

Ans

(a) Different kinds of packaging materials are:
1. Plastic covers that are used for the packaging of clothes.
2. Cardboard that is used for cartons of fruits, clothes etc.
3. Wooden boxes that are used for packaging of delicate items, fruits etc.

(b) Instead of keeping clothes in plastic covers, they can be kept in paper covers. Paper covers reduce garbage production, as paper can be recycled to get useful products.
(c) Packaging increases the amount of garbage as we keep on throwing the packaging materials carelessly on roads and other places. Also, since these packaging materials (mainly plastic covers) are non-recyclable, they keep lying on the roads and cannot be properly disposed off. Sometimes, they get into drains and sewer systems and block them, creating more problems.

Q.87 Do you think it is better to use compost instead of chemical fertilisers? Why?

Ans

Yes, it is better to use compost instead of chemical fertilisers. The reasons are:
1. Preparation of compost helps in reduction of waste that can be decomposed.
2. Compost is environment friendly as compared to the chemical fertilisers.
3. Use of compost helps in reducing soil pollution and water pollution.

Q.88 Fill in the blanks:

(a) Joints of the bones help in the _______ of the body.
(b) A combination of bones and cartilages forms the _______ of the body.
(c) The bones at the elbow are joined by a _____ joint.
(d) The contraction of the ______ pulls the bones during movement.

Ans

(a) Joints of the bones help in the movement of the body.
(b) A combination of bones and cartilages forms the skeleton of the body.
(c) The bones at the elbow are joined by a hinge joint.
(d) The contraction of the muscles pulls the bones during movement.

Q.89 Indicate true (T) and false (F) among the following sentences.

(a) The movement and locomotion of all the animals is exactly the same. ( )
(b) The cartilages are harder than bones. ( )
(c) The finger bones do not have joints. ( )
(d) The fore arm has two bones. ( )
(e) Cockroaches have an outer skeleton. ( )

Ans

(a) The movement and locomotion of all the animals is exactly the same. (F)
(b) The cartilages are harder than bones. (F)
(c) The finger bones do not have joints. (F)
(d) The fore arm has two bones. (T)
(e) Cockroaches have an outer skeleton. (T)

Q.90 Match the items in Column I with one or more items of Column II.

Column I Column II
Upper Jaw have fins on the body
Fish has an outer skeleton
Ribs can fly in the air
Snail is an immovable joint
Cockroach protect the heart
shows very slow movement
have a streamlined body

Ans

Column I Column II
Upper Jaw is an immovable joint
Fish have fins on the body skeleton,have a streamlined body
Ribs protect the heart
Snail shows very slow movement
Cockroach can fly in the air,has an outer skeleton

Q.91 Answer the following:

(a) What is a ball and socket joint?
(b) Which of the skull bones are movable?
(c) Why can our elbow not move backwards?

Ans

(a) Ball and socket joint is a type of joint that allows movement in all directions. It is a joint in which a rounded surface of bone moves within a cup-like cavity of another bone. Ball and socket joint is present in shoulder joint and hip joint.
(b) Lower jaw of the skull bone is movable.
(c) Our elbow cannot move backward because it has hinge joint which only allows movement in one plane.

Q.92 Name the major nutrients in our food.

Ans

The major nutrients present in our food are: carbohydrates, proteins, fats, vitamins and minerals.

Q.93 Name the following:

(a) The nutrients which mainly give energy to our body.

(b) The nutrients that are needed for the growth and maintenance of our body.

(c) A vitamin required for maintaining good eyesight.

(d) A mineral that is required for keeping our bones healthy.

Ans

(a) Carbohydrates and fats

(b) Proteins and minerals

(c) Vitamin A

(d) Calcium

Q.94 Name two foods each rich in

(a) Fats

(b) Starch

(c) Dietary fibre

(d) Protein

Ans

Nutrient Food source
(a) Fats Butter and nuts
(b) Starch Rice and potato
(c) Dietary fibre Green leafy vegetables and fruits
(d) Protein Egg and Pulses

Q.95 Tick (√) the statements that are correct.

(a) By eating rice alone, we can fulfill nutritional requirement of our body. ( )

(b) Deficiency diseases can be prevented by eating a balanced diet. ( )

(c) Balanced diet for the body should contain a variety of food items. ( )

(d) Meat alone is sufficient to provide all nutrients to the body. ( )

Ans

(a) By eating rice alone, we can fulfill nutritional requirement of our body. (X)

(b) Deficiency diseases can be prevented by eating a balanced diet. (√)

(c) Balanced diet for the body should contain a variety of food items. (√)

(d) Meat alone is sufficient to provide all nutrients to the body. (X)

Q.96 Fill in the blanks

(a) _______ is caused by deficiency of vitamin D.

(b) Deficiency of _________ causes a disease known as beri-beri.

(c) Deficiency of vitamin C causes a disease known as __________.

(d) Night-blindness is caused due to deficiency of ___________ in our food.

Ans

(a) Rickets is caused by deficiency of vitamin D.

(b) Deficiency of vitamin B1 causes a disease known as beri-beri.

(c) Deficiency of vitamin C causes a disease known as scurvy.

(d) Night-blindness is caused due to deficiency of vitamin A in our food.

Q.97 Correct the following statements and rewrite them in your notebook.

(a) Stem absorbs water and minerals from the soil.
(b) Leaves hold the plant upright.
(c) Roots conduct water to the leaves.
(d) The number of petals and stamens in a flower is always equal.
(e) If the sepals of a flower are joined together, its petals are also joined together.
(f) If the petals of a flower are joined together, then the pistil is joined to the petal.

Ans

(a) Roots absorb water and minerals from the soil.
(b) Stem holds the plant upright.
(c) Stem conducts water to the leaves.
(d) The number of petals and stamens in a flower may not be always equal.
(e) If the sepals of a flower are joined together, its petals are separate and are not joined together.
(f) If the petals of a flower are joined together, then the pistil is not necessarily joined to the petal.

Q.98 Draw (a) a leaf, (b) a taproot and (c) a flower, you have studied for Table 7.3.

Ans

(a) a leaf of rose plant

(b) taproot of rose plant

(c) a flower of rose plant

Q.99 Can you find a plant in your house or in your neighborhood, which has a long but weak stem? Write its name. In which category will you place it?

Ans

In our house or in our neighbourhood, the plant found with a long but weak stem is money plant. This plant can be classified as a climber because it takes support on its neighbouring structures and climb up.

Q.100 What is the function of a stem?

Ans

Functions of stem in a plant are:

1. The stem provides support to the plant.

2. It conducts water and minerals from the roots of the plant to its leaves and various other parts.

3. It also transports food prepared in leaves to other parts of the plant.

Q.101 Which of the following leaves have reticulate venation?

Wheat, tulsi, maize, grass, coriander (dhania), China rose

Ans

The leaves that have reticulate venation are tulsi, coriander (dhania) and China rose.

Q.102 If a plant has fibrous root, what type of venation do its leaves have?

Ans

If a plant has fibrous root, the venation present in its leaves is parallel.

Q.103 If a plant has leaves with reticulate venation, what kind of roots will it have?

Ans

Plants having leaves with reticulate venation will have tap roots.

Q.104 What are the parts of a flower.

Ans

Names of the parts of a flower are:
Sepals, petals, stamen (filament and anther) and pistil (stigma, style and ovary)

Q.105 From the following plants, which of them have flowers?

Grass, maize, wheat, chilli, tomato, tulsi, peepal, shisham, banyan, mango, jamun, guava, pomegranate, papaya, banana, lemon, sugarcane, potato, groundnut

Ans

All the plants mentioned here bear flowers. Plants like grass, tulsi and peepal bear very small flowers.

Q.106 Name the part of plant which produces food. Name the process.

Ans

In plants, food is produced in leaves by the process of photosynthesis.

Q.107 In which part of a flower, you are likely to find the ovary?

Ans

In the flower, ovary is found in the swollen and lowermost part of the pistil.

Q.108 Name two plants in which one has joined sepals and the other has separate sepals.

Ans

Flowers with joined sepals are: China rose and tomato.

Flowers with separate sepals are: Rose and jasmine.

Q.109 Do you find that all living beings need the same kind of food?

Ans

No, all living organisms do not require the same kind of food. Some organisms feed only on plants and plant products, some organisms feed on other living organisms and some organisms feed both on plants and animals. Based on the type of food they eat, living organisms are categorised as:

  1. Herbivores: the animals that eat plant and plant products, such as cow, deer, goat, etc.
  2. Carnivores: the animals that eat other animals, such as tiger, lion, etc.
  3. Omnivores: the animals that eat both plants and animals, such as crow, man, etc.

Q.110 Name five plants and their parts that we eat.

Ans

Name of plant Edible Plant Part
Potato Stem
Tomato Fruit
Spinach Leaf
Radish Root
Cauliflower Flower

Q.111 Match the items given in column A with that in column B.

Column A Column B
Milk, curd,paneer, ghee eat other animals
Spinach,cauliflower, carrot eat plants and plant products
Lions and tigers are vegetables
Herbivores are all animal products

Ans

Column A Column B
Milk, curd,paneer, ghee are all animal products
Spinach,cauliflower, carrot are vegetables
Lions and tigers eat other animals
Herbivores eat plants and plant products

Q.112 Fill up the blanks with the words given:

herbivore, plant, milk, sugarcane, carnivore

(a) Tiger is a __________ because it eats only meat.

(b) Deer eats only plant products and so, is called _________.

(c) Parrot eats only ________ products.

(d) The ________ that we drink, which comes from cows, buffaloes and goats is an animal product.

(e) We get sugar from ________.

Ans

(a) Tiger is a carnivore because it eats only meat.

(b) Deer eats only plant products and so, is called herbivore.

(c) Parrot eats only plant products.

(d) The milk that we drink, which comes from cows, buffaloes and goats is an animal product.

(e) We get sugar from sugarcane.

Q.113 What is a habitat?

Ans

Habitat is a place or environment where an organism lives. Habitat fulfills the requirement of food, shelter, air, water and other needs of an organism that are necessary for its survival.

Q.114 How are cactus adapted to survive in a desert?

Ans

Cactus is adapted to survive in the hot and dry conditions of a desert. Following are the adaptations that help a cactus to survive in desert:

1. Leaves of cactus are present in the form of spine to reduce water loss by transpiration.

2. Roots of cactus are very long that go deep inside the soil to absorb water.

3. Stem of cactus has a thick waxy coating that helps in water retention.

Q.115 Fill up the blanks

(a) The presence of specific features, which enable a plant or an animal to live in a particular habitat, is called _______.
(b) The habitats of plants and animals that live on land are called _____habitat.
(c) The habitats of plants and animals that live in water are called _______ habitat.
(d) Soil, water and air are the ______ factors of a habitat.
(e) Changes in our surroundings that make us respond to them, are called _________.

Ans

(a) The presence of specific features, which enable a plant or an animal to live in a particular habitat, is called adaptation.
(b) The habitats of plants and animals that live on land are called terrestrial habitat.
(c) The habitats of plants and animals that live in water are called aquatic habitat.
(d) Soil, water and air are the abiotic factors of a habitat.
(e) Changes in our surroundings that make us respond to them, are called stimuli.

Q.116 Which of the things in the following list are nonliving?

Plough, Mushroom, Sewing machine, Radio, Boat, Water hyacinth, Earthworm

Ans

In the above mentioned list, plough, sewing machine, radio and boat, are nonliving.

Q.117 Give an example of a non-living thing, which shows any two characteristics of living things?

Ans

Vehicles such as cars, buses, etc. show following two characteristics of living things:

1. Movement, and

2. Energy requirement

Q.118 Which of the non-living things listed below, were once part of a living thing?

Butter, Leather, Soil, Wool, Electric bulb, Cooking oil, Salt, Apple, Rubber

Ans

The non-living things butter, leather, wool, cooking oil, apple and rubber were once part of a living thing.

Q.119 List the common characteristics of the living things.

Ans

Following are common characteristics of living things:

  1. Growth
  2. Feeding
  3. Respiration
  4. Excretion
  5. Movement
  6. Reproduction
  7. Response to stimuli

Q.120 Explain why speed is important for survival in the grassland for animals that live there. (Hint: There are few trees or places for animals to hide in grasslands habitats.)

Ans

In grasslands, mainly grasses are found with a very few trees. Big carnivores such as lions, tigers etc. feed upon their preys that are found in these grasslands. It is very easy to find their prey in these regions, as there is hardly any space to hide. Preys are left with only one choice that is running from their predators. Hence, to protect themselves from their predators, preys adapt themselves by increasing their speed and increase their chance of survival in these regions.

Q.121 Is it possible for you to find out whether a plant has taproot or fibrous roots by looking at the impression of its leaf on a sheet of paper?

Ans

Yes, the type of roots can be determined by looking at the impression of the plant leaf on a paper. If the impression of the leaf shows reticulate venation, that is, if there is a net-like impression on both the sides of midrib, then the plant has taproots. However, if the impression of the leaf shows parallel venation, then the plant has fibrous roots.

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