Question

Which one of the following is not an annelid?
A. Nereis
B. Pheretima
C. Hirudinaria
D. Urchin

Answer 1

Hint:- Annelid is a phylum of invertebrate worms. About 17,000 species of annelids are known and they are segmented worms. They belong to the kingdom Animalia. Mostly annelids are found in a wet environment. Their body is composed of one or more body segments. Each segment possesses 1 or more rings. These rings are known as annuli.

Complete Answer:-
Nereis is a genus of worms that belongs to the phylum Annelida. It comprises various species, maximum of which are marine. For locomotion, they have setae and parapodia. Setae are of two types, which are formed on the parapodia. Acicular setae that give the support and Locomotor setae are for crawling. These worms are generally known as ragworms. Their body is cylindrical, long, and dorsoventrally flattened. Pheretemia is a genus of worms that belongs to the phylum Annelida. It iṣs nocturnal. They have a clitellum known as a band of glandular tissue existing on segments 14 to 16.
Hirudinaria belongs to the phylum Annelida and is commonly known as a common Indian leech. The body is soft, elongated, dorsoventrally flattened, about 30-35 cm long, and comprises 33 segments. It generally needs shallow water like freshwater tanks, ponds, lakes, etc. Sea urchin belongs to the phylum Echinodermata. They are generally spiked and spherical sea creatures. They crawl with the help of the tube feet and sometimes push themselves with their spines.
Thus, the right option is D.

Note:- About 950 species of sea urchin living on the seabed, occupying all ponds and depth zones from the intertidal to 5,000 meters. Their hard crusts are spherical and pointed, generally from 3 to 10 cm across. Sea urchin nourishes mainly on algae but sometimes they feed on sessile creatures or slow-moving.