$(a)$ 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.

(N/A) The three ways by which pests attack plants are:
$(i)$ They cut the root,stem,and leaf.
$(ii)$ They suck the cell sap from various parts of the plant.
$(iii)$ They bore into the stem and fruit.
$(b)$ The chemicals used to control pests are collectively known as pesticides (e.g.,insecticides,herbicides,or fungicides).
$(c)$ Excessive use of these chemicals should be avoided because:
$(i)$ They are toxic and can be harmful to non-target beneficial organisms,including humans and animals.
$(ii)$ They cause environmental pollution by contaminating soil and water sources.
$(iii)$ Pests may develop resistance to these chemicals over time,making them ineffective.