Botryoidal tissue is found in

Leech is:

What is the phenomenon called where the body of some animals is divided into identical segments both externally and internally?

In which of the following is the clitellum absent?

$A$: 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.

The phylum $Annelida$ is named so because of: