Question

Chaeta of Pheretima is about
A. 0.0025mm long
B. 0.25mm long
C. 0.05mm long
D. 2.5mm long

Answer 1

Hint: Pheretima is a genus of earthworms. This is commonly found in New Guinea and some parts of Southeast Asia. The species which belong to this genus Pheretima possess a clitellum. This is a band of glandular tissue present on segments 14 to 16.

Complete answer:
The earthworms are a type of animal that lives in the soil belonging to the phylum Annelida. They are important in aerating and draining the soil. They also help in burying organic matter in the soil.

Pheretima is a genus of earthworms. There is a clitellum present in those species which belong to the genus Pheretima. This clitellum is a band of glandular tissue and presents on segments 14 to 16. The chaita mainly functions for locomotion. Its appearance shows a chitinous region in a bristle form i.e. chaeta is a chitinous bristle. This is found in the insects. This is also found in some members of Arthropoda. In the case of phylum Annelida, it is also present in the family of worms and Pheretima is a genus that belongs to the family of worms.

The chaeta performs its functions in various other regions. The chaeta region shows a long and cylindrical appearance. Its diameter defines the shape of its and it holds a diameter of 0.25mm long.

Hence, the correct answer is option (B).

Additional information:
The Pheretima are individually hermaphroditic. The reproduction seen in the Pheretima can be either sexual or parthenogenetic. Female genital pores are present on the ventral surface of segment 14. There is a pair of male genital pores that are present ventrally on segment 18. Genital papillae may also be present ventrally. The production of new and young Pheretima is without a larval stage and takes place in cocoons. Pheretima is generally nocturnal and has characteristics of aversion to light.

Note: Pheretima is a genus that belongs to the phylum of Annelida and the family of worms. Chaeta is a chitinous bristle which is present in an insect, arthropod, or annelid worms such as the earthworm. This chaeta is mainly involved in the locomotion of the earthworms. In Pheretima, the diameter of the chaeta is about 0.25mm long.