Question

Collar cells occur in which of the followiing?

• A. Sponges
• B. Hydra
• C. Sandworm
• D. Star fish

Answer 1

The correct option is A

Sponges

The correct option is A.

Explanation of the correct option:

1. Flagellated cells called collar cells line the canals and spongocoel of sponges.
2. These cells make up the inner layer of a sponge's body wall.
3. Choanoderm is another name for this inner layer.
4. Nutrition, respiration, circulation, excretion, and nutrition are all supported by these cells.

Explanation of the incorrect options:

Option B:

1. Hydra belongs to the phylum cnidaria.
2. Choanocytes are not present in this phylum.

Option C:

1. Sandworm is a member of the phylum annelida.
2. It is called a sandworm because it is frequently found buried in the sand.
3. It is sometimes referred to as clam worm since it coexists with clams.

Option D:

1. They belong to the phylum echinodermata.
2. Choanocytes are not present in this phylum.

Final answer:

Therefore, collar cells occur in sponges.