The body segments in earthworm are called

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.

Earthworms possess:

What type of digestion is observed in earthworms?

$A$ - Earthworms are farmer's friends.
$R$ - They help in the breakdown of complex organic matter as well as in loosening of the soil.

Why is the nerve ring considered the brain of the earthworm?