NEET Biology Animal Kingdom MCQs Set 29

Answer: (b) metatherians

Explanation:
1. Pouched mammals are marsupials, also called metatherians.
2. The female has a pouch (marsupium) with teats to rear the young.

Teacher's Note:
1. Prototherians lay eggs and eutherians are placental mammals.

Answer: (b) choanocytes

Explanation:
1. Sponges feed with the help of flagellated collar cells called choanocytes, which create the water current and trap food particles.
2. Pinacocytes form the outer covering.

Teacher's Note:
1. Link choanocytes with food capture.

Answer: (a) Liver

Explanation:
1. Chloragogen cells of the earthworm store glycogen and fat and take part in deamination and urea formation, so they resemble the vertebrate liver.
2. They are found around the gut.

Teacher's Note:
1. Compare organs by function.

Answer: (c) Cockroach and Pila

Explanation:
1. Haemocoel, a blood-filled body cavity, is found in arthropods and molluscs, such as cockroach and Pila.
2. The circulatory system of these animals is open.

Teacher's Note:
1. Hydra, Taenia and Ascaris have no haemocoel.

Answer: (c) trichome

Explanation:
1. A single filament of Nostoc without a mucilage sheath is a trichome.
2. A colony is a group of filaments in a mucilage and mycelium and hyphae belong to fungi.

Teacher's Note:
1. The word trichome is used for the cellular chain of cyanobacteria.

Answer: (a) radial symmetry

Explanation:
1. Animals attached to a substratum (sessile) generally have radial symmetry, so they can meet food from all directions.
2. Examples are Hydra and sea anemone.

Teacher's Note:
1. Free-moving animals are bilaterally symmetrical.

Answer: (c) chemical stimulus

Explanation:
1. Hydra recognises its prey by a chemical stimulus, such as the substances from the injured prey.
2. This leads to firing of the nematocysts.

Teacher's Note:
1. The nematocyst only captures the prey.

Answer: (b) Echinoidea

Explanation:
1. Aristotle's lantern is the chewing apparatus with five teeth in sea urchins, class Echinoidea.
2. Starfishes and brittle stars do not have it.

Teacher's Note:
1. It is a typical echinoderm structure.

Answer: (d) thoracico-lumbar region

Explanation:
1. Sympathetic nerves in mammals arise from the thoracic and lumbar regions of the spinal cord.
2. Parasympathetic fibres come from cranial and sacral regions.

Teacher's Note:
1. The cervical region has no sympathetic outflow.

Answer: (b) choanocytes

Explanation:
1. Water current in Leucosolenia (a sponge) is produced by the beating of flagella of the choanocytes.
2. Pinacocytes cover the body and archaeocytes help in digestion and regeneration.

Teacher's Note:
1. Choanocytes are the collar cells.

Answer: (d) Schistosoma

Explanation:
1. Schistosoma (blood fluke) is a flatworm.
2. Entamoeba and Plasmodium are protozoans, and Wuchereria is a roundworm.

Teacher's Note:
1. Platyhelminthes include Taenia and Fasciola also.

Answer: (c) 6,7, 8, 9

Explanation:
1. In earthworm the four pairs of spermathecae open in the intersegmental grooves of segments 5/6, 6/7, 7/8 and 8/9, so they are in segments 6, 7, 8 and 9.
2. They store sperm received during copulation.

Teacher's Note:
1. Learn the segment numbers of the reproductive organs.

Answer: (c) fishes

Explanation:
1. Weberian ossicles are a chain of four small bones that link the air bladder with the inner ear in many bony fishes.
2. They improve hearing.

Teacher's Note:
1. Frogs, snakes and birds lack them.

Answer: (b) heterocoelous

Explanation:
1. The vertebrae of birds are heterocoelous, with saddle-shaped articular surfaces, which makes the neck flexible.
2. Procoelous vertebrae are seen in reptiles and amphicoelous in fishes.

Teacher's Note:
1. Mammals have acoelous vertebrae.

Answer: (a) Ophiuroidea

Explanation:
1. The basket star is an ophiuroid, a class of echinoderms.
2. Sea urchins are echinoids, sea lilies are crinoids and starfishes are asteroids.

Teacher's Note:
1. Ophiuroids have long flexible arms.

Answer: (a) collaterial gland

Explanation:
1. The ootheca (egg case) of the female cockroach is formed by the secretion of the collaterial glands.
2. The mushroom gland is in the male.

Teacher's Note:
1. Each ootheca contains about 16 eggs.

Answer: (b) archaeocytes

Explanation:
1. Archaeocytes are totipotent amoeboid cells that can change to other cell types, so they give sponges the power of regeneration.
2. Sclerocytes make spicules.

Teacher's Note:
1. Learn the sponge cell types and functions.

Answer: (d) hypnotoxin

Explanation:
1. Hydra has four kinds of nematocysts, and the penetrant is the largest.
2. It injects hypnotoxin to paralyse the prey.

Teacher's Note:
1. Hence hypnotoxin is the poisonous fluid.