31 Years NEET Previous Year Questions: Animal Kingdom - 1 - NEET MCQ

• 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.
  Hence, statement a is incorrect.
• Comb Plates: Comb plates are a characteristic feature of ctenophores. They help in locomotion.
  Hence, statement d is incorrect.
• Roundworms: Roundworms belong to Phylum Aschelminthes and have organ-system level of body organisation.
  Hence, statement c is correct.
• Echinoderms: 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, statements b and e are correct.

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”

The correct option is D: Platyhelminthes

• 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.

Line in NCERT: "Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals with organ level of organisation."

• 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.

Line in NCERT: "Animals with notochord are called chordates and those animals which do not form this structure are called non-chordates, e.g., porifera to echinoderms."

• 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.

Similarities between Aves and Mammals are:

• Warm-blooded nature: Both are homeothermic (warm-blooded) animals they are able to maintain a constant body temperature.
• Both respire through the lungs.
• Ossified endoskeleton: An endoskeleton made of bones is known as an ossified endoskeleton. Most organisms like bony fishes, mammals, birds, and reptiles have an endoskeleton made purely out of bones and cartilage. In Aves endoskeleton is fully ossified (bony) and long bones are hollow with air cavities.
• Four-Chambered Heart: Both have a four-chambered heart.
• Fertilization: In both sexes are separate and fertilization is internal.

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. Chondrichthyes is a class that contains the cartilaginous fishes: they are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone.
• 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.

The correct option is A.

Explanation of correct option:

1. The phylum Porifera includes multicellular animals that are commonly called sponges. They exhibit the cellular level of organization; their body is a meshwork of cells.
2. Sponges possess a water transport system (canal) and an internal cavity (spongocoel).
3. The canal and spongocoel are lined by choanocytes (collar cells). Choanocytes are flagellated cells that help to filter water and food.
4. Sponges undergo indirect development. It is characterized by the presence of a larval stage which is morphologically different from the adult.

Explanation of incorrect option:

Option B:

1. The phylum Mollusca comprises bilaterally symmetrical and coelomate animals. Example: squid.
2. They are triploblastic and the level of organization is organ-system.

Option C:

1. Protozoans are eukaryotic, unicellular, and heterotrophs. Example: Amoeba.
2. They reproduce both sexually and asexually.

Option D:

1. The phylum Coelenterata (Cnidaria) includes aquatic animals that possess specialized cells called cnidoblasts. Example: corals.
2. They are diploblastic animals and exhibit tissue level of organization.

Final answer: Body having meshwork of cells, internal cavities lined with food filtering flagellated cells, and indirect development are the characteristics of phylum Porifera.

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

Line in NCERT: "Sponges reproduce asexually by fragmentation and sexually by formation of gametes. Fertilisation is internal and development is indirect having a larval stage which is morphologically distinct from the adult."

The correct option is C

Explanation of correct option

1. Petromyzon marinus or sea lamprey is a jawless marine migratory fish that spends most of its adult life in the sea.
2. Matured fish migrate from marine to freshwater and lay eggs in areas with high oxygen levels.
3. These ammocoetes hatch and, before metamorphosis, migrate to the sea.

Explanation of incorrect option

Option A: 
Myxine glutinosa or Atlantic hagfish are non-migratory marine organisms without copulatory organs.

Option B:
Neomyxine biniplicata or hagfishes are non-migratory marine organisms without copulatory organs.

Option D:
Eptatretus stoutii or Pacific hagfish are non-migratory marine organisms without copulatory organs.

Final answer: A jawless fish that lays eggs in freshwater and whose ammocoetes larvae after metamorphosis return to the ocean is Petromyzon.

NCERT Reference: Page no. 56 of topic “4.2.11.1 Class – Cyclostomata” of chapter 4.

Line in NCERT: "Cyclostomes are marine but migrate for spawning to fresh water. After spawning, within a few days, they die. Their larvae, after metamorphosis, return to the ocean. Examples: Petromyzon (Lamprey) and Myxine (Hagfish)."

• Animals that give birth to offspring are called viviparous.
• Platypus is an oviparous animal (egg-laying). It belongs to the class- Mammalia. The platypus (Ornithorhynchus anatinus), also known as the duck-billed platypus, is a semiaquatic egg-laying monotreme.
• Elephant, Whale and Flying fox are viviparous animals. All mammals are viviparous except monotremes. It is the only mammals that lay eggs instead of giving birth to live young.

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.

Line in NCERT: "Some members like Planaria possess high regeneration capacity."

• 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.

Topic in NCERT: Class - Chondrichthyes

Line in NCERT: "Some of them have electric organs (e.g., Torpedo) and some possess poison sting (e.g., Trygon)."

• 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.

Line in NCERT: "The body of arthropods is covered by chitinous exoskeleton."