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

(N/A) $\Rightarrow$ Earthworms are known as 'friends of farmers' because they make burrows in the soil,which makes the soil porous.
This porosity helps in the respiration of soil organisms and facilitates the easy penetration of developing plant roots.
Furthermore,earthworms increase soil fertility by breaking down organic matter,a process known as vermicomposting.
They also help in turning over the soil,which improves its nutrient content.