NCERT Exemplar Class 9 Science Chapter 7 Diversity in Living Organisms are part of NCERT Exemplar Class 9 Science. Here we have given NCERT Exemplar Class 9 Science Solutions Chapter 7 Diversity in Living Organisms.

NCERT Exemplar Class 9 Science Solutions Chapter 7 Diversity in Living Organisms

Question 1.
Find out incorrect sentence.
(a) Protista includes unicellular eukaryotic organisms.
(b) Whittaker considered cell structure, mode and source of nutrition for classifying the organisms in five kingdoms.
(c) Both Monera and Protista may be autotrophic and heterotrophic.
(d) Monerans have well defined nucleus.
Solution:
(d) Members of Kingdom Monera are prokaryotic organisms. They have typical prokaryotic cellular structure characterised by the absence of a well defined nucleus and all membrane bound cell organelles. Members of Kingdom Monera include bacteria, cyanobacteria (blue green algae) etc.

Question 2.
Which among the following have specialised tissue for conduction of water?
(i) Thallophyta
(ii Bryophyta
(ii Pteridophyta
(iv Gymnosperms
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Solution:
(c) InKingdomPlantae,vasculartissues i.e., specialised tissues for the conduction of water and minerals (xylem) and for the translocation of food (phloem) are present in the groups Pteridophyta, Gymnospermae and Angiospermae. The groups Thallophyta and Bryophyta do not possess vascular tissues for the conduction of water, minerals and food.

Question 3.
Which among the following produce seeds?
(a) Thallophyta
(b) Bryophyta
(c) Pteridophyta
(d) Gymnosperms
Solution:
(d) Gymnosperms (Gt/mwos-naked, sperma-seed) are the group of plants which possess naked seeds, and are usually perennial, evergreen and woody. Examples of some gymnosperms are Pinus, Cycas, Cedrus etc. Thallophyta, Bryophyta and Pteridophyta are the groups of plants that do not bear seeds at all.

Question 4.
Which one is a true fish?
(a) Jelly fish
(b) Star fish
(c) Dog fish
(d) Silver fish
Solution:
(c) Jelly fish (Aurelia), star fish (Asterias) and silver fish (Lepisma) belong to the phyla Coelenterata, Echinodermata and Arthropoda respectively and are all invertebrates. Dog fish (Scoliodon) is a true fish that belongs to Class Pisces of Vertebrata.

Question 5.
Which among the following is exclusively marine?
(a) Porifera
(b) Echinodermata
(c) Mollusca
(d) Pisces
Solution:
(b) All the known members of Phylum Echinodermata (the spiny skinned animals) are exclusively marine. Members of Phylum Porifera are mostly marine, rarely fresh water (e.g. Spongilla). Members of Phylum Mollusca are mostly marine. Many, however occur in fresh water (e.g. Unio) and some even in damp soil (e.g. some snails and slugs). Members of Class Pisces are both marine as well as fresh water.

Question 6.
Which among the circulatory system?
(i) Arthropoda
(ii ) Mollusca
(iii) Annelida
(iv)Coelenterata
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (ii) and (iv)
Solution:
(a) In open circulatory system, blood flows in open spaces and bathes the cells directly. It does not flow in well-defined blood vessels. Examples-Arthropoda and Mollusca (except cuttle fish).
In closed circulatory system, blood circulates inside the blood vessels without ever coming in direct contact with the body cells. Examples- Annelida and Chordata.
Blood is not present in the phyla Porifera, Coelenterata, Ctenophora, Platyhelminthes and Aschelminthes.

Question 7.
In which group of animals, coelom is filled with blood?
(a) Arthropoda
(b) Annelida
(c) Nematoda
(d) Echinodermata
Solution:
(a) Due to the presence of open circulatory system in the Phyla Arthropoda and Mollusca, the coelomic cavity (or coelom) is filled with blood and is referred to as haemocoel.

Question 8.
Elephantiasis is caused by
(a) Wuchereria
(b) pinworm
(c) planarians
(d) liver flukes.
Solution:
(a) Wftchereria (filarial worm) is a parasitic worm belonging to Phylum Aschelminthes (Nematoda) and the causal organism of disease elephantiasis (or filariasis). The disease is spread by female Culex mosquitoes from affected individuals to healthy individuals. The disease is characterised by swelling of the legs and/or scrotum.

Question 9.
Which one is the most striking or (common) character of the vertebrates?
(a) Presence of notochord
(b) Presence of triploblastic condition
(c) Presence of gill pouches
(d) Presence of coelom
Solution:
(a) Notochord is a solid, unjointed, rod-like structure situated on the dorsal side between the dorsal, hollow nerve cord and the alimentary canal. Presence of notochord is one of the characteristic features of chordates including vertebrates. In vertebrates, notochord is only present in the embryonic stage, and is replaced by a cartilagenous or bony vertebral column in the adults.

Question 10.
Which among the following have scales?
(i) Amphibians
(ii) Pisces
(iii) Reptiles
(iv) Mammals
(a) (i) and (iii)
(b) (iii) and (iv)
(c) (ii) and (iii)
(d) (i) and (ii)
Solution:
(c)

Question 11.
Find out the false statement.
(a) Aves are warm blooded, egg laying and have four chambered heart.
(b) Aves have feather covered body, forelimbs are modified as wing and breathe through lungs.
(c) Most of the mammals are viviparous.
(d) Fishes, amphibians and reptiles are oviparous.
Solution:
(None): Aves (birds) are warm blooded animals and have a four-chambered heart. They are oviparous (egg laying). There is an outside covering of feathers, and two forelimbs are modified into wings for flight. They respire by means of lungs.
Most of the mammals are viviparous i.e., they give birth to young ones, except some like duck-billed platypus. (These are called egg laying mammals).
Fish, amphibians and reptiles are all oviparous i.e., they lay eggs except a few.

Question 12.
Pteridophyta do not have
(a) root
(b) stem
(c) flowers
(d) leaves.
Solution:
(c) The plant body of pteridophytes is differentiated into roots, stem and leaves. Pteridophytes do not possess flowers. Flowers are the reproductive organs which are borne by angiosperms only.

Question 13.
Identify a member of Porifera.
(a) Spongilla
(b) Euglena
(c) Penicillium
(d) Hydra
Solution:
(a) Spongilla (fresh water sponge) is a member of Phylum Porifera. Euglena belongs to Kingdom Protista, Penicillium belongs to Kingdom Fungi and Hydra befongs to Phylum Coelenterata (Kingdom Animalia).

Question 14.
Which is not an aquatic animal?
(a) Hydra
(b) Jelly fish
(c) Corals
(d) Filaria
Solution:
(None): Hydra, jelly fish (Aurelia) and corals are all coelenterates and are aquatic. Filaria is a disease which is caused by filarial worm (Wuchereria). It is a parasite that lives in the lymphatic system of human beings.

Question 15.
Amphibians do not have
(a) three chambered heart
(b) gills or lungs
(c) scales
(d) mucus glands.
Solution:
(c) Amphibians have a three-chambered heart comprising of two atria and one ventricle. The respiratory organs are skin, ’ lungs, buccopharyngeal cavity and gills. Their skin contains mucus glands which keep it moist. Amphibians do not possess scales on their body.

Question 16.
Organisms without nucleus and cell organelles belong to
(i) fungi
(ii) Protista
(iii) cyanobacteria
(iv)archaebacteria.
(a) (i) and (ii)
(b)n(iii) and (iv)
(c) (1) and (iv)
(d) (ii) and (iii)
Solution:
(b) Kingdom Monera contains all prokaryotic organisms such as bacteria, archaebacteria, cyanobacteria, mycoplasma etc. These organisms have prokaryotic cellular structure characterised by absence of well organelles.

Question 17.
Which of the following is not a criterion for classification of living organisms?
(a) Body design of the organism
(b) Ability to produce one’s own food
(c) Membrane bound nucleus and cell organelles
(d) Height of the plant
(d) (ii) and (iii)
Solution:
(d) Height is a feature that depends on several factors like environment, nutrition etc. besides genes, thus all the members of a single species can have different heights and two different species can have similar range of height, thus including height as criterion of classification is not practical.

Question 18.
The feature that is not a characteristic of protochordata is
(a) presence of notochord
(b) bilateral symmetry and coelom
(c) jointed legs
(d) presence of circulatory system.
Solution:
(c) Animals belonging to the group Protochordata possess notochord, at least at some stage in their lives. Protochordates are bilaterally symmetrical, triploblastic and have a true coelom. They possess a closed circulatory system. Protochordates do not have jointed legs.

Question 19.
The locomotory organs of Echinodermata are
(a) tube feet
(b) muscular feet
(c) jointed legs
(d) parapodia.
Solution:
(a) Echinoderms possess a peculiar water-driven tube system called water vascular system. Tube feet of this system help the animal in locomotion, capturing food and respiration.

Question 20.
Corals are
(a) poriferans attached to some solid support
(b) cnidarians, that are solitary living
(c) poriferans present at the sea bed
(d) cnidarians that live in colonies.
Solution:
(d) Corals are cnidarians (coelenterates) that live in colonies. Examples of some corals are Corallium (red coral), Meandrina (brain coral), Astraea (star coral) etc.

Question 21.
Who introduced the system of scientific nomenclature of organisms?
(a) Robert Whittaker
(b) Carolus Linnaeus
(c) Robert Hooke
(d) Ernst Haeckel
Solution:
(b) Gaspard Bauhin (also called Casper Bauhin) a Swiss physician, and botanist, introduced a system of scientific binomial nomenclature of naming plants. This system was later developed by Carolus Linnaeus (1751). Carolus Linnaeus is considered the Father of binomial nomenclature.

Question 22.
Two chambered heart occurs in
(a) crocodiles
(b) fish
(c) aves
(d) amphibians.
Solution:
(b) Fish (Class Pisces) have a two-chambered heart with an atrium and a ventricle (exception being lungfish which have three-chambered heart). Amphibians (Class-Amphibia) and reptiles (except crocodiles and their relatives) have three-chambered heart with two atria and one ventricle. Crocodiles and birds (Class-Aves) and mammals have four chambered heart with two atria and two ventricles.

Question 23.
Skeleton is made entirely of cartilage in
(a) sharks
(b) tuna
(c) rohu
(d) none of these.
Solution:
(a) The cartilaginous fish bear cartila¬ginous endoskeleton i.e. the endo-skeleton which is made entirely of cartilage, e.g. sharks (Scoliodon, etc.)
In the bony fish, endoskeleton is cartilaginous in the embryonic stage, but in the adults it is replaced by bones. Thus they have bony endoskeleton, e.g., Rohu, Tuna etc.

Question 24.
0ne of the following is not an Annelid:
(a) Nereis
(b) Earthworm
(c) Leech
(d) Urchins.
Solution:
(d) Urchins belong to the Phylum Echinodermata e.g. Echinus (sea urchin). Neries, Pheretima (earthworm) and Hirudinaria (leech) are all annelids.

Question 25.
The book Systema Naturae was written by
(a) Linnaeus
(b) Haeckel
(c) Whittaker
(d) Robert Brown
Solution:
(a) Carolus Linnaeus (Carl von Linne), a Swedish botanist, is known as the Father of Taxonomy. He developed the most widely applicable binomial system of nomenclature of organisms. ‘Systema naturae’ was one of his major publications. The first edition of this book was printed in the Netherlands (in 1735), which was a twelve-page work. By the time, it reached its 10th edition (in 1758), it classified 4400 species of animals and 7700 species of plants.

Question 26.
Carl von Linne was involved with which branch of science?
(a) Morphology
(b) Taxonomy
(c) Physiology
(d) Medicine.
Solution:
(b) Refer to answer 25.

Question 27.
Real organs are absent in
(a) Mollusca
(b) Coelenterata
(c) Arthropoda
(d) Echinodermata.
Solution:
(b) Phylum Coelenterata (Cnidaria) has tissue level of body organisation i.e. the cells are grouped together to form tissues, which then perform specific functions. Tissues are not further organised in organs. Therefore, real organs are absent in Coelenterata. On the other hand, in the phyla Arthropoda, Mollusca and Echinodermata, there is organ system level of body organisation i.e. tissues are organised to form organs, which together form an organ system.

Question 28.
Hard calcium carbonate structures are used as skeleton by
(a) Echinodermata
(b) Protochordata
(c) Arthropoda
(d) Nematoda.
Solution:
(a) In many echinoderms, the endoskeleton (skeleton present inside the body) is made up of hard calcium carbonate structures.

Question 29.
Differentiation in segmental fashion occurs in
(a) leech
(b) starfish
(c) snails
(d) Ascaris.
Solution:
(a) Annelids are bilaterally symmetrical, triploblastic animals with a true coelom. This allows true organs to be packaged in the body structure and therefore there is extensive organ differentiation. In annelids, this differentiation occurs in a segmental fashion, with the segments lined up one after the other from head to tail. Examples-earthworms, leeches etc.

Question 30.
ln taxonomic hierarchy family comes between
(a) class and order
(b) order and genus
(c) genus and species
(d) division and class.
Solution:
(b) Taxonomic hierarchy is a definite sequence of taxonomic categories arranged in descending order starting from kingdom and reaching up to species or an ascending order starting from species and reaching up to kingdom. The taxonomic hierarchy was first proposed by Carolus Linnaeus and it includes seven taxonomic categories, arranged in descending order as:
Kingdom → Phylum/Division → Class → Order → Family → Genus → Species
From the above hierarchy, it is clear that family comes between order and genus.

Question 31.
5-Kingdom classification was given by
(a) Morgan
(b) R. Whittaker
(c) Linnaeus
(d) Haeckel
Solution:
(b) Robert H. Whittaker (1969), an American taxonomist, proposed the most widely applicable 5-kingdom system of classification. This system divides all the organisms into five kingdoms named – as Monera, Protista, Fungi, Plantae and Animalia.

Question 32.
Well defined nucleus is absent in
(a) blue green algae
(b) diatoms
(c) algae
(d) yeast
Solution:
(a)Refer to answer 1.

Question 33.
The ‘Origin of Species’ is written by
(a) Linnaeus
(b) Darwin
(c) Hackel
(d) Whittaker.
Solution:
(b) Most life forms that we see today have arisen by an accumulation of changes in body design that allow the organism possessing them to survive better. Charles Darwin first described this idea of evolution in 1859 in his book, The Origin of Species.

Question 34.
Meena and Hari observed an animal in their garden. Hari called it an insect while Meena said it was an earthworm. Choose the character from the following which confirms that it is an insect.
(a) Bilateral symmetrical body.
(b) Body with jointed legs
(c) Cylindrical body
(d) Body with little segmentation
Solution:
(b) Insects are arthropods. Body with jointed legs is a characteristic feature of arthropods. Thus, presence of this feature in an invertebrate organism confirms that it is an arthropod.

Short Answer Type Questions

Question 35.
Write true (T) or false (F).
(a) Whittaker proposed five kingdom classification.
(b) Monera is divided into Archaebacteria and Eubacteria.
(c) Starting from class, species comes before the genus.
(d) Anabaena belongs to the Kingdom Monera.
(e) Blue green algae belongs to the Kingdom Protista.
(f) All prokaryotes are classified under Monera.
Solution:
(a) T
(b) T
(c) F-Starting from class, species comes after the genus.
(d) T
(e) F-Blue green algae belongs to the Kingdom Monera.
(f) T

Question 36.
Fill in the blanks.
(a) Fungi show ________ mode of nutrition.
(b) Cell wall of fungi is made up of ________ .
(c) Association between blue green algae and fungi is called as ________.
(d) Chemical nature of chitin is ________ .
(e) ________ has smallest number of organisms with maximum number of similar characters.
(f) Plants without well differentiated stem, roots and leaves are kept in ________.
(g) ________ are called as amphibians of the plant kingdom.
Solution:
(a) saprophytic
(b) chitin
(c) lichen
(d) carbohydrate
(e) Species
(f) Thallophyta
(g) Bryophytes

Question 37.
You are provided with the seeds of gram, wheat, rice, pumpkin, maize and pea. Classify them whether they are monocot or dicot.
Solution:
Dicot seeds: Gram, pumpkin, pea Monocot seeds: Wheat, rice, maize

Question 38.
Match items of column I with items of column II. Column II

Solution:
(a) B
(b) A
(c) D
(d) C
(e) F
(f) E
(g) G

Question 39.
Match items of column I with items of column II.Column I

Solution:
(a) C
(b) B
(c) F
(d) A
(e) E
(f) D

Question 40.
Classify the following organisms based on the absence/presence of true coelom (i.e., acoelomate, pseudocoelomate and coelomate).
Spongilla, Sea anemone, Planaria, Liver fluke, Wuchereria, Ascaris, Nereis, Earthworm, Scorpion, Birds, Fishes, Horse.
Solution:
Acoelomates: Spongilla, Sea anemone, Planaria, Liver fluke
Pseudocoelomates: Wuchereria, Ascaris
Coelomates: Nereis, Earthworm, Scorpion, Birds, Fishes and Horse.

Question 41.
Endoskeleton of fishes are made up of cartilage and bone; classify the following fishes as cartilagenous or bony.
Torpedo, Sting ray, Dog fish, Rohu, Anglerfish, Exocoetus.
Solution:
Cartilaginous fishes: Torpedo, Sting ray and Dog fish. Bony fishes: Rohu, Angler- fish and Exocoetus.

Question 42.
Classify the following based on number of chambers in their heart.
Rohu, Scoliodon, Frog, Salamander, Flying lizard, King cobra, Crocodile, Ostrich, Pigeon, Bat, Whale
Solution:
Two-chambered heart: Rohu, Scoliodon. Three-chambered heart: Frog, Salamander, Flying lizard, King cobra.
Four-chambered heart: Crocodile, Ostrich, Pigeon, Bat, Whale.

Question 43.
Classify Rohu, Scolidon, Flying lizard. King Cobra, Frog, Salamander, Ostrich, Pigeon, Bat, Crocodile and Whale into the cold blooded/ warm blooded animals.
Solution:
Warm-blooded animals: Ostrich, Pigeon, Bat, Whale.
Cold-blooded animals: Rohu, Scoliodon, Flying lizard, King cobra, Frog, Salamander, Crocodile.

Question 44.
Name two egg laying mammals.
Solution:
Two egg laying mammals are duckbilled platypus and Echidna (spiny ant eater).

Question 45.
Fill in the blanks.
(a) Five kingdom classification of living organisms is given by ______ .
(b) Basic smallest unit of classification is ______ .
(c) Prokaryotes are grouped in Kingdom ______ .
(d) Paramecium is a protist because of its ______.
(e) Fungi do not contain ______.
(f) A fungus ______ can be seen without microscope.
(g) Common fungi used in preparing the bread is ______ .
(h) Algae and fungi form symbiotic association called ______ .
Solution:
(a) R. Whittaker
(b) Species
(c) Monera
(d) Unicellular eukaryotic organisation
(e) chlorophyll;
(f) like mushroom
(g) yeast;
(h) lichens.

Question 46.
GiveTrue (T) and False (F).
(a) Gymnosperms differ from Angiosperms in having covered seed.
(b) Non-flowering plants are called Cryptogamae.
(c) Bryophytes have conducting tissue.
(d) Funaria is a moss.
(e) Compound leaves are found in many ferns.
(f) Seeds contain embryo.
Solution:
(a) False-Gymnosperms differ from angiosperms in having naked seeds.
(b) True
(c) False-Bryophytes do not have conducting (or vascular) tissues.
(d) True
(e) True
(f) True

Question 47.
Give examples for the following.
(a) Bilateral, dorsiventral symmetry is found in______ .
(b) Worm causing disease elephantiasis is______
(c) Open circulatory system is found in ______ where coelomic cavity is filled with blood.
(d) ______are known to have pseudocoelom.
Solution:
(a) flatworms (,e.g. liver fluke)
(b) filarial worm (e.g. Wuchereria)
(c) arthropods (e.g. cockroach) and molluscs (e.g. Pila)
(d) nematodes (e.g Ascaris)

Question 48.
Label a,b,c and d. given in Figure 7.1. Give the function of (b)

Solution:

Caudal or tail fin (b) acts as a steering organ and helps in swimming of fish.

Question 49.
Fill in the boxes given in Figure 7.2 with appropriate characteristics/plant group (s).

Solution:
(a) Thallophyta;
(b) Without vascular tissues;
(c) Pteridophyta;
(d) Phanerogams;
(e) Bear naked seeds;
(f) Angiosperms;
(g) Have seeds with two cotyledons;
(h) Monocots.

Long Answer Type Questions

Question 50.
Write names of few thallophytes. Draw a labelled diagram of Spirogyra.
Solution:
Names of some thallophytes are: Spirogyra, Ulothrix, Cladophora, Ulva, Chara, Laminaria, Gelidium etc. Labelled diagram of Spirogyra is as follows:

Question 51.
Thallophyta, Bryophyta and Pteridophyta are called as ‘cryptogams’. Gymnosperms and angiosperms are called as ‘phanerogams’. Discuss why? Draw one example of Gymnosperm.
Solution:
Thallophyta, Bryophyta ‘and Pterido¬phyta are called “cryptogams”(Kntyptos-hidden, gamos-to marry) as all these are seedless plants and have inconspicuous reproductive organs.
Gymnosperms and Angiosperms are collectively called “phanerogams” (Phaneros-visible, gamos-to marry) as both the groups have seeded plants and conspicuous reproductive organs.

Fig. A: Female Cycas plant
B: Male Cycas plant

Question 52.
Define the terms and give one example of each.
(a) Bilateral symmetry
(b) Coelom
(c)Triploblastic
Solution:
(a) BiFateral symmetry: It is a type of symmetry in which the body of an organism can be divided into two equal halves by a single plane passing through the longitudinal axis of the body. Exmaples-Planaria, earthworm, cockroach, all chordates such as birds, reptiles, humans etc.

(b) Coelom: Coelom is the internal body cavity between visceral organs and body wall in which well-developed organs can be accommodated. In some animals pseudocoelom is present (e.g. nematodes) which is a body cavity not lined by mesoderm. True coelom is lined by mesoderm and first appears in annelids. Examples of animals in which true coelom is present are Earthworm, cockroach, snail, all chordates such as birds, humans etc.

(c) Triploblastic: The term triploblastic refers to the animals which develop from three primary germ layers-ectoderm (outer), mesoderm (middle) and endoderm (inner). All animals from Phylum Platyhelminthes to Phylum Chordata are triploblastic animals. Examples- Tapeworm, Ascaris, cockroach, Pila, fish, frog, crocodile, mammals etc.

Question 53.
You are given leech, Nereis, Scolopendra, prawn and scorpion; and all have segmented body organisation. Will you classify them in one group? If no, give the important characters based on which you will separate these organisms into different groups.
Solution:
No, we will not classify all the given organisms in one group because there are some characteristic features by which these organisms can be separated from each other and placed in two different group.
Leech and Nereis are placed in Phylum Annelida because:

1. (i) Both of these have metamerically segmented body i.e. body is divided internally into many segments by septa. Body segments are lined up one after the other from head to tail.
2. (ii) These animals have closed circulatory system.
   Scolopendra, Prawn and scorpion are placed in Phylum Arthropoda because :
   • Their body is externally segmented and consists of head thorax and abdomen.
   • These animals have an open circulatory system and the coelomic cavity is blood-filled called haemocoel.

Question 54.
Which organism is more complex and evolved among bacteria, mushroom and mango tree. Give reasons.
Solution:
Mango tree is more complex and evolved among bacteria, mushroom and mango tree because :

1. Mango tree is a multicellular, eukaryotic and autotrophic organism.
2. It has well developed sporophytic plant body differentiated into roots, stem and leaves.
3. It has well developed vascular tissues i.e. xylem and phloem for conduction of water, minerals and food.
4. It contains seeds enclosed in fruits.
5. It contains an embryo stage.
   Bacteria are unicellular prokaryotic and primitive organisms. Mushroom (fungi) is multicellular and eukaryotic but without any differentiation of plant body into roots, stem and leaves. It does not possess vascular tissue, seed, embryo stage etc.

Question 55.
Differentiate between flying lizard and bird. Draw the diagram.
Solution:
Differences between flying lizard and bird are as follows :

(i)	It belongs to Class- Reptilia.	It belongs to Class-Aves.
(ii)	It is cold-blooded animal.	It is warm­blooded animal.
(iii)	Body is covered with scales.	Body is covered with feathers.
(iv)	It has three- chambered heart.	It has four-chambered heart.
(v)	Its forelimbs are with digits i.e. fingers.	Its forelimbs are modified into wings and without digits.
(vi)	It can fly by gliding in air for a short distance by extending the skin fold between its limbs.	It can fly by stroking its feathered wings and for long distances.

Question 56.
List out some common features in cat, rat and bat.
Solution:
Cat, rat and bat belong to Class- Mammalia and have following common features:

1. Presence of vertebral column.
2. Presence of hair, sweat glands and oil glands on skin.
3. All are warm-blooded.
4. Their females are viviparous.
5. Presence of 4-chambered heart.
6. Presence of mammary glands.
7. Presence of diaphragm.
8.  Presence of external ear.

Question 57.
Why do we keep both snake and turtle in the same class?
Solution:
Both snake and turtle are kept in the same Class Reptilia because they share reptilian characters like:

1. Presence of scales on the body.
2. Cold-blooded nature.
3. Respiration by lungs.
4. Three-chambered heart.
5. Laying eggs with tough coverings