NCERT Solutions Class 11 Biology Chapter 4

For some students, the CBSE Class 11 Biology first-term examinations can be intimidating. It is for this reason that the NCERT Solutions for Class 11 Biology Chapter 4 proves to be a great resource from both reference and studying perspectives. 

Class 11 Biology Chapter 4 NCERT Solutions are an important study material that will help you score well in your exam. Subject-matter experts at Extramarks have prepared the solutions ensuring that they have accurate answers along with relevant and appropriate explanations. 

NCERT Solutions for Class 11 Biology Chapter 4 – Animal Kingdom 

Class 11 Biology Chapter 4 NCERT Solutions Animal Kingdom provides students with answers to all the questions in the NCERT textbook. Access the solutions on Extramarks and take your exam preparation to the next level.

Access NCERT Solutions for Class 11 Biology Chapter 4 – Animal Kingdom


Animal Kingdom Class 11 NCERT Solutions – Download

Based on NCERT textbooks, Class 11 Animal Kingdom solutions are prepared by our subject-matter experts in a simple language. Diagrams and pictures are used, wherever possible, to ensure students understand the answers in a better way. 

CBSE Class 11 Biology Chapter 4 NCERT Solutions

Animal Kingdom is an important chapter that will help you achieve a high exam score. The NCERT Solutions for CBSE Class 11 Biology Chapter 4 will assist you in finding accurate answers to the questions that are given at the end of the chapter.  

Chapter 4 has six basic classifications of the animal kingdom namely – Symmetry, Segmentation, Diploblastic and Triploblastic Organisation, Coelom, and Notochord.

Key Features of NCERT Solutions for Class 11 Biology Chapter 4 – Animal Kingdom

  • Simple and easy to understand. 
  • Subject-matter experts have framed the solutions, so it is error-free.
  • Students can access the solutions anytime, anywhere.

Animal Kingdom Class 11 NCERT Solutions – Marks Distribution

Biology has a total of 70 marks for theory and 30 marks for the practical exam. Unit 1 Animal Kingdom, which includes Chapter 4 of Class 11 Biology NCERT Solutions, comes for roughly 10 marks as per the marking scheme. Excluding the viva and practical aspects of the chapter, we can conclude that the Animal Kingdom chapter will be worth 2 to 5 marks in your written exams. 

The NCERT Solutions for Class 11 Biology Chapter 4 will help students find the right answers to NCERT textbook questions, and perform better in the exams. 

Benefits of Class 11 Biology NCERT Solutions Chapter 4

Class 11 Biology NCERT Solutions Chapter 4 will assist students in fully understanding the chapter. Some advantages of referring to the Animal Kingdom NCERT Solutions Class 11 of Extramarks are listed below:

  • The NCERT Solutions include answers that are precise and accurate. Both long and short answers have been included so that the students are able to understand the topic thoroughly
  • The solutions have been prepared by subject-matter experts at Extramarks.
  • The NCERT Solutions for Class 11 Biology Chapter 4 has answers to all the NCERT textbook questions and is made as per the latest guidelines of CBSE.

Q.1 What are the difficulties that you would face in classification of animals, if common fundamental features are not taken into account?


For classification of animals, various common features such as the arrangement of cells, body symmetry, nature of coelom, circulatory system, the pattern of digestive system or reproductive system are taken into consideration. If these common features are not considered, the classification of each organism would become very difficult and chaotic. Classification of animals also helps in comparing different organisms. So, if only a single characteristic is considered while classifying the living organisms then the main objective would not be fulfilled. Thus, to study the classification of animals then it has to be based on various common basic features. This process also helps in the addition of new discovery into the respective group.

Q.2 If you are given a specimen, what are the steps that you would follow to classify it?


Taxonomy is the study of principles and procedures of classification. Classification is the arrangement of living things according to their similarities and differences which bring order in the vast assemblage of living things in the world. A specimen can be classified in a stepwise process using the following classification categories:

Q.3 How useful is the study of the nature of the body cavity and coelom in the classification of animals?


Coelom is a fluid-filled cavity formed between the gut wall and the body wall lined by the mesodermal cells. Presence or absence of coelom is an important criterion for animal classification. The animals with bilateral symmetry are further classified into three types of groups based on the presence or absence of coelom. They are as follows:

  1. Coelomates: In these animals, true coelom lined by mesoderm is present. E.g. Annelids, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata
  2. Pseudocoelomates: In these animals, the body cavity is not lined by mesoderm instead the mesoderm is present in scattered pouches between the ectoderm and the endoderm. E.g. Aschelminthes
  3. Acoelomates: In these animals, body cavity is absent. E.g. Platyhelminthes

Q.4 Distinguish between intracellular and extracellular digestion?


Q.5 What is the difference between direct and indirect development?


Direct development Indirect development
Direct development has a larval stage that is morphologically distinct from the adult. In indirect development, larval stage is absent, the embryo develops into a mature organism (looks like a miniature adult) without entering into the larval stage.
A process called metamorphosis transforms the larva into a mature adult. In indirect development, metamorphosis is absent.
It is found in invertebrates and amphibians. It is found in fishes, reptiles and mammals.

Q.6 What are the peculiar features that you find in parasitic platyhelminthes?


The peculiar features of parasitic platyhelminthes are as follows:

  1. Hooks and suckers are present to attach to the wall of the gut.
  2. They have an extra coating (of glycocalyx) to protect themselves from being digested in the gut.
  3. They absorb nutrients from the host directly through their body surface. Their digestive systems are less evolved as compared to the free-living platyhelminthes.
  4. Locomotory organs like cilia and sensory organs like the primitive eye are absent in the parasitic forms of flatworms.
  5. Parasitic flatworms are mostly hermaphrodite ensuring reproduction in the host. The reproductive capacity is enhanced with most of their body lumen packed with testes and eggs.

Q.7 What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?


Arthropoda is the largest phylum of animal kingdom. Over two-thirds of all known species on earth are arthropods. The following are the reasons for arthropods to constitute the largest group of the animal kingdom:

  1. Arthropods are very diverse in structure and form.
  2. Their diversity in form is responsible for their dispersion into varied habitats. Arthropods are known to inhabit the ocean depths to the tallest mountain peaks.
  3. Their hard exoskeleton made of chitin is tough and protects the animal from extreme dryness. The exoskeleton is also insoluble in water, weak alkaline and acidic solutions.
  4. They have joint appendages that allow for efficient and precise movements. Many appendages are modified to meet the need of the arthropod for a specific foraging behaviour or a habitat.
  5. Their reproductive cycle is short and the female lays numerous eggs at one time.

Q.8 Water vascular system is the characteristic of which group of the following:

(a) Porifera
(b) Ctenophora
(c) Echinodermata
(d) Chordata


Water vascular system is the characteristic of Echinodermata.

Q.9 “All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement.


To understand the above statement, one needs to define the two words – notochord and vertebra – from which the terms chordates and vertebrates are derived.

Notochord: The notochord is a flexible rod-shaped structure found in embryos of all chordates.

Vertebral column: The vertebral column, also known as backbone or spine, is a bony structure found in vertebrates. It is formed from individual bones called vertebrae.

Chordata is a phylum which is divided into three subphyla – Urochordata, Cephalochordata and Vertebrata. All the chordates at some point of their lives possess a notochord. However, in vertebrates, this notochord is replaced by the vertebral column in the adult stage. Hence, it is right to state that “All vertebrates are chordates but all chordates are not vertebrates”.

Q.10 How important is the presence of air bladder in Pisces?


Air bladder or swim bladder is a sac filled with air that regulates buoyancy in fishes. It plays a very important role in Pisces. The fishes (like Osteichthyes) where air bladder is present, it plays the following roles:

  • The air bladder controls the buoyancy by enabling the fish to stay at a particular water depth without having to waste energy in swimming continuously.
  • It acts as a resonating chamber to produce or receive sound.

In another kind of fishes (like Chondrichthyes), the air bladder is absent. Therefore these fishes have to swim constantly to avoid sinking resulting in the consumption of a lot of energy.

Q.11 What are the modifications that are observed in birds that help them fly?


Some of the modifications that help birds to fly are listed below:

  1. The forelimbs are modified into wings.
  2. Birds have feathers that help them fly, steer and balance.
  3. Long bones are hollow with air cavities making their body weight light.
  4. Birds have air sacs that connect to the lungs and provide them with additional oxygen which is essential for flying.
  5. Birds have well-developed eyesight and brains that help them gauge any approaching danger as well as to forage for food.

Q.12 Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?


An oviparous mother lays more eggs at one time as compared to the number of offspring a viviparous mother gives birth to at any given time. This is because of the following reasons:

  • In oviparous mother, the eggs are laid soon after fertilisation, or eggs are externally fertilised. Therefore many eggs can be laid at one time. This also provides an evolutionary advantage as many eggs are liable to be eaten, destroyed during the period of development.
  • In the case of the viviparous mother, she has to house the embryo in the uterus till the full term of development. The embryo also draws nutrition from its mother. The mother thus is constrained by space in the uterus.

Q.13 Segmentation in the body is first observed in which of the following:

(a) Platyhelminthes
(b) Aschelminthes
(c) Annelida
(d) Arthropoda


(c) Annelida

Q.14 Match the following:

(a) Operculum (i) Ctenophora
(b) Parapodia (ii) Mollusca
(c) Scales (iii) Porifera
(d) Comb plates (iv) Reptilia
(e) Radula (v) Annelida
(f ) Hairs (vi) Cyclostomata and Chondrichthyes
(g) Choanocytes (vii) Mammalia
(h) Gill slits (viii) Osteichthyes


(a) Operculum (viii) Osteichthyes
(b) Parapodia (v) Annelida
(c) Scales (iv) Reptilia
(d) Comb plates (i) Ctenophora
(e) Radula (ii) Mollusca
(f) Hair (vii) Mammalia
(g) Choanocytes (iii) Porifera
(h) Gill slits (vi) Cyclostomata and Chondrichtyes

Q.15 Prepare a list of some animals that are found parasitic on human beings.


Endoparasite –

Cause infection inside the body

Taenia(Tapeworm), Parasitic worms can cause a number of problems, including diarrhoea, fatigue, skin rash, nervousness, asthma and anaemia.
Fasciola(Liver fluke).
Ascaris(Round Worm)
Wuchereria(Filaria worm)
Plasmodium Malaria
Entameoba Amoebiasis
Trypanosomabrucei African sleeping sickness
Ectoparasites – Cause infection within the skin Pediculushumanuscapitis Head lice
Phthitus pubis Pubic lice


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FAQs (Frequently Asked Questions)

1. From where can I access NCERT solutions of CBSE Biology Class 11 Chapter 4 Animal Kingdom?

Students can access NCERT solutions of CBSE Biology Class 11 Chapter 4 on Extramarks. The solutions are prepared by subject-matter experts, so students can rely on them completely for their exam preparation.

2. What is the CBSE Class 11 Biology Chapter 4 about?

Chapter 4 of Class 11 Biology introduces students to the Animal Kingdom, where they will learn that classification can be based on a variety of factors such as cell arrangement, body symmetry, coelom type, digestive, circulatory, reproductive system patterns, and so on. Symmetry, Diploblastic and Triploblastic Organisation, Coelom, Segmentation, and Notochord are the six basic classifications of the animal kingdom.

3. Discuss the significance of Coelom or body cavity in the Classification of Animals.

The Coelom or body cavity is a fluid-filled space between the body wall and digestive tract of animals. It acts as a cavity for other organs in animals. The absence or presence of Coelom plays an essential role in the classification of animals. Based on the nature and presence of Coelom or body cavity, animals can be classified into – Coelomates, Pseudocoelomates and Acoelomates.

4. Arthropods are considered the largest species in the Animal Kingdom. Explain.

Arthropods are one of the most thriving animals. Being the largest group in the animal kingdom, they have captured land, sea and air, and rank in distribution from mountain peaks to deep seas. They are known to be three-fourths of the currently identified living and fossil organisms. The thick, non-living chitinous integument develops their exoskeleton, which protects them from their predators, prevents water loss and helps them in resisting high temperatures up to 100 °C or more. An example of arthropods that can endure nuclear radiation is cockroaches. They can also reproduce fast and even in less time. All these factors make them the largest species in the animal kingdom.

5. Explain the adaptations that help birds to fly.

Birds have undergone many structural adaptations or modifications that help them to fly (i.e. in their aerial life). Some of these modifications are: 

  • They have a streamlined body that helps them in their rapid and smooth movement in the air. 
  • Their body is covered with feathers for insulation. 
  • Their forelimbs are modified into wings, and they use their hind limbs for walking, perching, and swimming. 
  • The presence of pneumatic bones reduces their body weight, so they can fly.
  • Additional air sacs are present in their bodies that supplement respiration.


6. Is it possible that the number of eggs or young ones produced by viviparous and oviparous mothers is equal? Explain.

The number of eggs produced by an Oviparous mother can be more than the number of young ones produced by a Viviparous mother because, in the case of Oviparous animals, the development takes place outside the mother’s body. As a result, their eggs are more prone to predators and environmental conditions outside. Thus, to overcome loss from such factors, more eggs are produced by Oviparous mothers to ensure that even under harsh environmental conditions, some eggs can survive and produce young ones. 

On the other hand, in the case of Viviparous mothers, the development of young ones takes place in safe conditions inside their bodies. As a result, they are less exposed to risk factors. Therefore, it can be concluded that fewer young ones are produced compared to Oviparous mothers. 


7. List out a few animals that are found parasitic on human beings as discussed in Chapter 4 of NCERT Solutions for Class 11 Biology.

Some animals that are found parasitic on human beings as discussed in Chapter 4 of NCERT Solutions for Class 11 Biology include–

  • Ascaris or Roundworm
  • Taenia or Tapeworm
  •  Enterobius or Pinworm
  • Ancylostoma or Hookworm
  • Wuchereria or Filarial worm