Question

The most common earthworm in India is
A. Pheretima communissima
B. Eutyphacus
C. Pheretima posthuma
D. Lumbricus

Answer 1

Hint: Annelids are small worm-like invertebrates also known as the ringed worms or segmented worms. They are a large phylum of extant species including ragworms, earthworms, and leeches. Species belonging to the genus Pheretima have a clitellum, which is a band of glandular tissue present on segments 14 to 16.

Complete answer:
Annelids are a phylum of invertebrate segmented worms with over 17,000 known species that inhabit several geographical locations. Well, known species of annelids are earthworms, ragworms, and leeches. Annelids are mostly found in moist wet environments and can be considered to be parasitic or mutualistic. Pheretima posthuma is generally nocturnal, like most earthworms, and has an aversion to light. They come out only at night and feed and reproduce only at night. Similar to most earthworms, they must keep their body surface wet to respire. They are also called farmer's friends as they help in making the soil porous for easy irrigation.

Hence, the correct answer is Option C.

Additional information:
Annelids have one or more body segments, each having one or more rings which are called annuli. Annelids reproduce sexually by hermaphroditic cross-fertilization and can regenerate cut off pieces of their body. Unlike sponges, which can come back together if ripped apart. They have a hydrostatic skeleton, a one-way digestion system, and bilateral symmetry.

Note: Lumbricus is a genus of earthworms that are commonly seen in Europe. This genus comprises nearly 700 valid species. Earthworms are also oligochaetes which are soil-dwelling annelids. Eutyphocus is one of the rare species of earthworms found in India. These earthworms are said to be found in the northeast regions of India and not much is known about this species of earthworm. Pheretima communissima is a species of earthworm native to regions of China and East Asian countries.