What type of muscles are present in the body wall of animals belonging to the phylum $Annelida$?

Metameric segmentation is exhibited by which of the following animals?

$A$ student was given a specimen to identify on the basis of the characteristics given below.
$(i)$ They are metamerically segmented.
$(ii)$ Presence of closed circulatory system.
$(iii)$ They have circular and longitudinal muscles for locomotion.
Identify the specimen.

What does a sandworm (Nereis) possess for locomotion?

The distinctive feature of $Phylum$ $Annelida$ is:

Closed circulatory system is found in?