NCERT Solutions for Class 7 Science Chapter 10 : Respiration in Organisms


Why does an athlete breathe faster and deeper than usual after finishing the race?


The body of an athlete, who runs in a race, requires more oxygen. Therefore, his breathing rate increases so as to supply more oxygen to the body cells. This is why an athlete, after finishing the race, breathes deeper and faster than usual. 


The mountaineers carry oxygen with them because:
(a) At an altitude of more than 5 km there is no air.
(b) The amount of air available to a person is less than that available on the ground.
(c) The temperature of air is higher than that on the ground.
(d) The pressure of air is higher than that on the ground.


The mountaineers carry oxygen with them because: (b) The amount of air available to a person is less than that available on the ground.


Tick the correct answer:
(a) In cockroaches, air enters the body through
(i) lungs
(ii) gills
(iii) spiracles
(iv) skin

(b) During heavy exercise, we get cramps in the legs due to the accumulation of
(i) carbon dioxide
(ii) lactic acid
(iii) alcohol
(iv) water

(c) Normal range of breathing rate per minute in an average adult person at rest is:
(i) 9-12
(ii) 15-18
(iii) 21-24
(iv) 30-33

(d) During exhalation, the ribs
(i) move outwards
(ii) move downwards
(iii) move upwards
(iv) do not move at all


(a) In cockroaches, air enters the body through (iii) spiracles.
(b) During heavy exercise, we get cramps in the legs due to the accumulation of (ii) lactic acid.
(c) Normal range of breathing rate per minute in an average adult person at rest is: (ii) 15-18.
(d) During exhalation, the ribs (ii) move downwards.


Why do we often sneeze when we inhale a lot of dust-laden air?


We often sneeze on inhaling dust-laden air because dust particles get entangled in the hair present in the nostrils which irritate the nasal membrane and cause sneezing. Hair found in the nostrils prevents entry of dust particles into lungs and sneezing expels them from the nose, allowing only clean air to enter the lungs.


Match the items in Column I with those in Column II:
Column I Column II
(a) Yeast (i) Earthworm
(b) Diaphragm (ii) Gills
(c) Skin (iii) Alcohol
(d) Leaves (iv) Chest cavity
(e) Fish (v) Stomata
(f) Frog (vi) Lungs and skin
(vii) Tracheae


The correctly matched contents of Column I with Column II are as follows:

Column I

Column II

(a) Yeast

(iii) Alcohol

(b) Diaphragm

(iv) Chest cavity

(c) Skin

(i) Earthworm

(d) Leaves

(v) Stomata

(e) Fish

(ii) Gills

(f) Frog

(vi) Lungs and skin


Take three test-tubes. Fill ¾th of each with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2?


All the organisms produce carbon dioxide and water as the final products of respiration.

Test tube A will have the highest concentration of CO2 because the snail kept in it produces carbon dioxide by the process of respiration. On the other hand, test tube B will have the least concentration of carbon dioxide among the three because the water plant performs photosynthesis during which carbon dioxide is utilised and oxygen is produced. In the test tube C, carbon dioxide produced by the snail and by the plant is used up in the process of photosynthesis performed by the plant.


List the similarities and differences between aerobic and anaerobic respiration.


Similarities between aerobic and anaerobic respiration are:

1. Energy is produced.

2. Carbon dioxide is released.

Differences between aerobic and anaerobic respiration are:


Mark ‘T’ if the statement is true and ‘F’ if it is false:
(i) During heavy exercise the breathing rate of a person slows down. (T/F)
(ii) Plants carry out photosynthesis only during the day and respiration only at night. (T/F)
(iii) Frogs breathe through their skins as well as their lungs. (T/F)
(iv) The fishes have lungs for respiration. (T/F)
(v) The size of the chest cavity increases during inhalation. (T/F)


(i) False
(ii) False
(iii) True
(iv) False
(v) True

Benefits of NCERT Solutions

Following are some of the benefits of using NCERT Solutions by Extramarks.

1. The NCERT solutions for class 7 are prepared keeping in mind the necessary rules and format issued by the CBSE board thus providing students much-needed preview of the exam pattern of questions and preview of the exam that they are going to face during the final exams.

2. The students can be sure about the quality of the solutions as they are committed by highly experienced and expert teachers. These teachers have years of experience and they make sure that there is no mistake committed when preparing the solutions.

3. The NCERT 7 solutions are provided for the questions that are most likely to appear in the exam thus improving the efficiency of the students by helping them prepare for the important parts of the syllabus.

Tips & Strategies for Class 7 Exam Preparation

1. Start your revision early so you can revise well and grasp all the difficult concepts.

2. Organize your study time by making a timetable as it will help you manage your time accordingly.

3. Take mock tests and solve sample papers as they will help you learn time management during the exam and make you familiar with the exam pattern.

4. Take regular breaks, look after yourself by sleeping properly and eating well.

5. Know your exam well, explore the mock tests, and practice sample papers as much as you can.

Why Choose Extramarks CBSE Class 7 Study Materials?

1. The solutions have been compiled keeping in mind the purpose of scoring high marks in exams thus they have everything that the students need to prepare for exams.
2. The NCERT solutions for class 7 are designed in a clear and simple language complete with diagrams so that the students understand the subject well.
3. The NCERT 7 solutions are accurate thus improving their reliability.
4. The solutions are designed by expert and experienced teachers that help in removing all doubts out of the solutions and improving the credibility of the answers.

Frequently Asked Questions

Is class 7 Math NCERT book sufficient for prepare for the exams?

Yes, the NCERT book has been designed keeping in mind the pattern of paper that will be presented in the exam to students. The NCERT book is sufficient to study for the exam as it has everything related to the exam and contains all information out of which the questions will be asked in the exam. But if you want to prepare a little bit extra, we suggest that you go through the NCERT class 7 solutions.

When to refer to NCERT solutions for class 7th?

When you are studying the NCERT book for math and other subjects for your class 7 exams, refer to the NCERT class 7 solutions simultaneously so you can see where you are going wrong and what are you getting right in your exercises’ attempt.

Why are the NCERT solutions important for Class 7th?

The class 7th is very crucial as it is among the major middle school classes during which the child’s base is formed in math and science and even in other subjects like English. Thus, it is students must study smartly in this class and ace their exams while getting all the help they need from the NCERT 7 solutions given by Extramarks.

Can I rely on the NCERT solutions for class 7 Math at Extramarks to perform well in the annual exam?

Yes, absolutely. The NCERT solutions provided by Extramarks for class 7 are eloquent and elaborate at best and are thus useful for students studying for the final exams of class 7. The students will have many questions and doubts regarding the NCERT solutions for class 7 and this is why the solutions have been elaborated well to help students understand the answers to exercises.

Do you provide NCERT solutions for Class 7 Math for free?

Yes, the NCERT solutions for Math and other subjects for class 7 are available for free from Extramarks.

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