How many pairs of pores of spermathecae are present in an earthworm (in $pairs$)?

Following are the statements about the prostomium of an earthworm.
$(a)$ It serves as a covering for the mouth.
$(b)$ It helps to open cracks in the soil into which it can crawl.
$(c)$ It is one of the sensory structures.
$(d)$ It is the first body segment.
Choose the correct answer from the options given below.

In $Pheretima$,the organisms obtain their nutrition from:

Distinguish between the following: Prostomium and peristomium.

How many genital pores are present in an earthworm?

Fertilization in earthworm is