31 Years NEET Previous Year Questions: Animal Kingdom - 1

• Those cnidarians which exist in both forms exhibit alternation of generation (Metagenesis), i.e., polyps produce medusae asexually and medusae form the polyps sexually (e.g., Obelia). Metagenesis is not observed in Helminths.
• Comb plates are a characteristic feature of ctenophores. They help in locomotion.
• Roundworms belong to Phylum Aschelminthes and have organ-system level of body organisation.
• They are triploblastic and coelomate animals.
• The echinoderms have three primary germ layers during development and hence are triploblastic. Echinoderms are coelomates as the cavity between the body wall and alimentary canal is lined by mesoderm. The most distinctive feature of echinoderms is the presence of water vascular system which helps in locomotion, capture and transport of food and respiration.

Hence, the correct option is B.
NCERT Reference: Refer topics “4.2.2 Phylum – Coelenterata (Cnidaria)”, “4.2.3 Phylum – Ctenophora”, “4.2.5 Phylum – Aschelminthes” and “4.2.9 Phylum – Echinodermata”

• Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals with organ level of organisation.
• Aschelminthes is triploblastic, bilaterally symmetrical and pseudocoelomate.
• Annelida is triploblastic, bilaterally symmetrical and acoelomate.
• Ctenophora is radially symmetrical, diploblastic.

Hence, the correct option is D.
NCERT Reference: Page no. 51 of topic “4.2.4 Phylum – Platyhelminthes” of chapter 4.

• True segmentation is present in Annelida, Arthropoda and Chordata.
• They also have an organ-system level of organisation, bilateral symmetry and are true coelomates.
• On the other hand, molluscs have an unsegmented body.

Hence, the correct option is B.
NCERT Reference: Refer topics “4.2.6 Phylum – Annelida”, “4.2.7 Phylum – Arthropoda” and “4.2.11 Phylum – Chordata” of chapter 4.

• Metamorphosis is the process of transformation of an immature larva into an adult form in two or more distinct stages.
• Animals that undergo metamorphosis are said to have indirect development, e.g., tunicates, moths, starfish, etc.
• In the case of earthworms, development is direct which means no larval stage is present and hence, there is no metamorphosis.

Hence, the correct option is A.
NCERT Reference: Page no. 56 of topic “4.2.11.1 Class – Cyclostomata” of chapter 4.

• Giving birth to living young that develop within the mother's body rather than hatching from eggs is called viviparity.
• All mammals except the monotremes are viviparous. Birds are oviparous and mammals are viviparous.

Hence, the correct option is C.
NCERT Reference: Refer topic “4.2.11.6 Class – Aves” and “4.2.11.7 Class – Mammalia” of chapter 4.

• Chondrichthyes always have a cartilaginous endoskeleton.
• Most mammals are viviparous, giving birth to live young. However, the five species of monotreme, the platypuses and the echidnas lay eggs.
• Chordates have jawless animals (Agnatha) as well.
• Most reptiles have 3 chambered heart. Crocodilians have 4 chambered hearts. Turtles have 3 chambered heart but with an incomplete wall in the single ventricle, so their hearts are functionally 4 chambered.

Hence, the correct option is A
NCERT Reference: Page no. 56 of topic “4.2.11.2 Class – Chondrichthyes” of chapter 4.

• Phylum Porifera (the sponges) has a cellular level of body organisation, with an inner cellular layer consisting of highly specialised flagellated cells called choanocytes (or collar cells).
• The development in this phylum is indirect as it includes a free-swimming larva called amphiblastula or parenchymula for dispersal of the species.

Hence, the correct option is A
NCERT Reference: Pge no. 49 of topic “4.2.1 Phylum – Porifera” of chapter 4.

• Petromyzon (Lamprey) 
  Class: Cyclostomata 
  Phylum: Chordata
• It is a jawless fish that lays eggs in freshwater. The eggs hatch in about 3 weeks into minute transparent larvae called ammocoetes.
• After metamorphosis, the young lampreys swim down to the sea where they remain for 3 or 4 years before reaching maturity when they once again migrate to streams or rivers to spawn and die.
• Gonads become mature at that time when adults return to rivers for spawning.

Hence, the correct option is C
NCERT Reference: Page no. 56 of topic “4.2.11.1 Class – Cyclostomata” of chapter 4.

• Platypus is an oviparous animal (egg-laying). It belongs to the class- Mammalia.
• Elephant, Whale and Flying fox are viviparous animals.

Hence, the correct option is B.
NCERT Reference: Page no. 60 of topic “4.2.11.7 Class – Mammalia” of chapter 4.

• Cnidarians are aquatic, mostly marine, solitary or colonial sessile or free-swimming radially symmetry animals while members of Ctenophora, Cephalochordata, Echinodermata are found exclusively in the marine environment.

So the correct answer is 'Cnidaria'.

Hence, the correct option is D.
NCERT Reference: Page no. 50 of topic “4.2.2 Phylum – Coelenterata (Cnidaria)” of chapter 4,

• Gorgonia belongs to cnidaria class- Anthozoa (animal).
• Gorgonians are also known as sea whips or sea fans and are similar to the sea pen, a soft coral.
• These marine invertebrates are multi-cellular, have no cell walls (a characteristic of plants), most have tissues (organized groups of cells), and all are heterotrophic, i.e., they cannot manufacture their own food and depend on other organisms for nutrition.

Hence, the correct option is B.
NCERT Reference: Page no. 50 of topic “4.2.2 Phylum – Coelenterata (Cnidaria)” of chapter 4.

• Planaria is a flatworm that possesses a high power of regeneration due to the neoplastic cells which are found in them.
• If an individual is cut transversely into two parts, the anterior segment will generate a new tail and the posterior end will develop a new head.

Hence, the correct option is B.
NCERT Reference: Page no. 51 of topic “4.2.4 Phylum – Platyhelminthes” of chapter 4.

• Torpedo is electric ray. Torpedo is a sluggish fish. It is carnivorous. The prey is firstly killed by electric shock. The shock can also be harmful to human beings.
• Pristis is a sawfish.
• Trygon is sting ray
• Scoliodon is a dog fish.

Hence, the correct option is B.

NCERT Reference: Page no. 57 of topic “4.2.11.2 Class – Chondrichthyes” of chapter 4.

• Cyclostomata have sucking and circular mouth without jaws. Median fins (appendages) are present but paired fins (appendages) are absent. Integuments are without scales.
•  In aves, forelimbs are modified into wings for flying and hind limbs are used for walking and running. The body is covered with feathers. Skin is thin, dry and non-glandular. Lungs have air sacs. 
• In mammals, mammary glands are present for the nourishment of the young ones. Hairs are present on the body. They have 2 pairs of limbs. Pinnae are absent in monotreme (mammals that lay eggs). 
• Chondrichthyes have a persistent notochord, placoid scales as the exoskeleton and ventrally positioned mouth. Gill slits are not covered by an operculum. 

Hence, the correct option is A.
NCERT Reference: Page no. 56 of topic “4.2.11.2 Class – Chondrichthyes” of chapter 4.

• Parapodia are present in aquatic annelids like Nereis, which help them in swimming.
• The other three features, i.e. metameric segmentation, jointed appendages and chitinous exoskeleton are present in phylum-Arthropoda. 

Hence, the correct option is C
NCERT Reference: Page no. 52 of topic “4.2.6 Phylum – Annelida” of chapter 4.