In which of the following classes of Annelida are one pair of ovaries and several pairs of testes found?

Which of the following animal groups exhibits bilateral symmetry,is coelomate,triploblastic,and shows metameric segmentation?

Metamerism or metameric segmentation is a characteristic feature of

What is the color of the blood in the phylum Annelida?

$A$: True coelom originated for the first time in phylum $Annelida$.
$R$: It allowed the animal to have an alimentary canal longer than the body and space for storing gametes.

Suctorial mouth occurs in