The body is segmented in:

Given below are two statements. One is labelled as Assertion $(A)$ and other is labelled as its Reason $(R)$.
Assertion $(A) :$ In $Nereis$,longitudinal and circular muscles help in locomotion.
Reason $(R) :$ $Nereis$ is an aquatic annelid which is monoecious and possesses lateral appendages called parapodia,which help in swimming.

Which is not a feature of $Annelida$?

The enzyme $Hirudin$ is present in the saliva of which of the following?

True coelom appeared first in the course of evolution in

Write the general characters of Phylum Annelida.