In earthworm,fertilization occurs in

Which structure in the earthworm is capable of secreting hormones?

Identify the correct terms for the following analogy:
$(i)$ Excretory organ in cockroach : Malpighian tubules :: In earthworm : ...........
(ii) Scientific name of cockroach : Periplaneta americana :: Scientific name of earthworm : ...........

The copulation period of an Earthworm is:

Select the correct option regarding blood plasma/fluid for humans and earthworms.

The approximate number of earthworms found in $1$ acre of land is..........