Which of the following organisms contains hemoglobin in its blood plasma?

Leech is:

Name the animal having both setae and nephridia.

The phylum $Annelida$ is named so because 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.

What is the phenomenon called where the body of some animals is externally and internally divided into segments with a serial repetition of at least some organs?