Which of the following is/are true about the endostyle in Urochordates?

Question

Which of the following is/are true about the endostyle in Urochordates?

I. It is involved in filter feeding.

II. It secretes mucus to trap food particles.

III. It is homologous to the thyroid gland in vertebrates.

IV. It is present only in the larval stage.

1. A. I and II
2. B. I, II, and III (Correct answer)
3. C. II and IV
4. D. All of the above

Correct Answer

Option B — I, II, and III

Detailed Solution & Explanation

The correct answer is I, II, and III.

Key Points

• I, II, and III are correct.
• The endostyle is a ciliated groove in the pharynx involved in filter feeding via mucus.
• It is homologous to the vertebrate thyroid gland.
• Statement IV is incorrect - the endostyle is present in adult tunicates (not only larvae).