Which of the following annelids is dioecious (unisexual)?

True coelom or body cavity occurs in

In which of the following is the respiratory pigment $Chlorocruorin$ found?

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?

Larval stages are absent in the life cycle of . . . . . . .

Haemoglobin is dissolved in the blood plasma of: