Metamerism is a characteristic of

$A$ 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.

In which of the following is true metamerism first observed?

Earthworm belongs to which of the following phyla?

Which of the following is an invertebrate,triploblastic,and coelomate organism?

In $Leech$,excretion occurs through ...... .