Question

The main function of clitellum is:
A. Cocoon formation
B. Locomotion
C. Excretion
D. Copulation

Answer 1

Hint: Clitellum is a structure which is found mostly in earthworm and leeches. The entire body of the earthworm is segmented except for this region. It is the glandular section of the body which is located on the anterior side of the body of the leeches and earthworms.

Complete answer:
To know the correct answer to the question, we must be well aware of the clitellum.

Clitellum is a dark band of thickened glandular tissue which is found on the 14-16 segment of the body of earthworms. We all know that the body of the earthworm is divided into many segments. The clitellum further divides its body into three prominent regions: Preclitellar region, clitellar region and the postclitellar region.
The clitellum has the female genital aperture on it. In fact, the clitellum is only visible on the worm when it is sexually mature.
It secretes a sac in which the eggs of the worm are stored. Further, the oviducts of the worm coming from the ovarian funnel join together and open here on the ventral side of the clitellum.

Since, we are well aware of the clitellum and its function therefore the correct answer to the question is cocoon formation.

Note: Here, it must be noted that the clitellum is not only responsible for the formation of the cocoon but also for the secretion of the cocoon for the eggs.
Further, whenever the clitellum turns orange, it is an indication that the earthworm is ready to mate.