One of the oldest uses of earthworm is as

The locomotory organ of an earthworm is ..........

An animal that depends on organic matter,dead insects,and its own cuticle for food is known as a .....

Which of the following are the types of septal nephridia found in earthworms?

Identify the incorrect statements among the following:
$(a)$ In earthworm,a single male genital pore is present.
$(b)$ Setae help in locomotion of earthworm.
$(c)$ The muscular layer in the body wall of earthworm is made up of only circular muscles.
$(d)$ Typhlosole is a part of the intestine of earthworm.

Give scientific reasons: Earthworm is known as the farmer's friend.