$(i)$ State three ways by which pests attack plants.
$(ii)$ Name the chemicals used to control pests.
$(iii)$ Explain why excessive use of such chemicals should be avoided.

(N/A) $(i)$ Pests attack plants in the following ways:
$(a)$ They cut the root,stem,and leaf of plants.
$(b)$ They suck the cell sap from various parts of the plant.
$(c)$ They bore into the stem and fruit.
$(ii)$ The chemicals used to control pests are collectively known as pesticides,which include insecticides,herbicides,and fungicides.
$(iii)$ Excessive use of these chemicals should be avoided because:
$(a)$ They are toxic and can be poisonous to many non-target plant and animal species.
$(b)$ They cause environmental pollution by contaminating soil and water sources.
$(c)$ They can accumulate in the food chain,leading to biomagnification.