Question

Rows of S-shaped setae in the body of earthworm are present in all the segments, except

• A. The first segment
• B. The last segment
• C. The first and last segment
• D. The first, last and clitellum

Answer 1

The Correct Option is D

The correct answer is:

Option 4: The first, last and clitellum

Explanation:

Setae are small bristle-like structures that are used by earthworms for locomotion. Rows of S-shaped setae are found on the body segments of an earthworm.

However, setae are absent in the first segment, the last segment, and the clitellum (the thickened region used for reproduction, typically found in segments 32 to 37).

The absence of setae in these segments helps with the earthworm's movement and reproduction. The clitellum produces mucus for the formation of the cocoon during reproduction, while the first and last segments do not require setae for movement.

Thus, setae are absent in the first segment, the last segment, and the clitellum.