Question

Earthworms have how many segments?
A. $85 - 400$
B. $100 - 200$
C. $20 - 95$
D. $115 - 120$

Answer 1

Hint: Earthworm belongs to the Phylum: Annelida, Class: Oligochaeta, Genus: Pheretima, and Species: Posthuma. They are soft-bodied animals living under damp soil within burrows, which come out of the holes during the nighttime for feeding. During the rainy season, the burrows are filled with water so they leave the burrows and creep on the moist surface of the soil.

Complete answer:
Usually the body of the earthworm is divided into $100 - 120$ true segments, the first segment is known as peristomium which surrounds the mouth opening. Each segment of the body except the first, clitellar, and last segment bears numerous “S” shaped hard chitinous structures called setae or chaetae arranged in form of ring round each of the segments that act as holdfast during the locomotion over the ground and act as the attaching structure in burrows.

Hence option D is the correct option.

Additional Information:
Nor $85$ or $400$ segments are seen in the case of earthworms,
hence option A is incorrect.

Some earthworms can have $100$ segments but $200$ segmented earthworms are not seen hence the option B is incorrect.

An earthworm has more than $20$ segments, hence option C is incorrect.

Note. :
Overhanging the mouth on the dorsal surface is a small fleshy lobe, the prostomium which is considered as a pseudo segment and serves as a covering for the mouth. The distal end of each seta is pointed but the proximal end of the setae is blunt and the middle swollen part is known as nodulus. The entire body is covered externally by a thin transparent noncellular cuticle, perforated by numerous pores containing epidermal glands.