What type of methods are used before grains are stored for future use?

$(a)$ State three ways by which pests attack the plants.
$(b)$ Name the chemical used to control pests.
$(c)$ Explain why excessive use of such chemicals should be avoided.

Sid went to market to buy foodgrains for his home and on returning when his mother found the grains discoloured and of low and poor quality,she returned them back to the vendor. The vendor told Sid's mother that it was due to the storage loss of the grains that resulted in their poor quality and gave her the good quality grains.
$(a)$ What kind of qualities are shown by Sid's mother?
$(b)$ What could be the control measures to prevent this storage loss?

Discuss why pesticides are used in very accurate concentration and in a very appropriate manner.

$(a)$ State two characteristics of a healthy animal.
$(b)$ State any four characteristics of storage structure for grains.

Why should biological control methods be preferred for protecting crops?