Question

Pesticides are used to protect crops from insects and other pests. But sometimes pesticides can be as harmful as they are useful. How can pesticides be harmful?
Responses
A Pesticides are usually mild and most insects are not affected by it.Pesticides are usually mild and most insects are not affected by it.
B Pesticides are very expensive and few farmers can afford to use them.Pesticides are very expensive and few farmers can afford to use them.
C Insects become resistant to pesticides after being exposed to it for some time.Insects become resistant to pesticides after being exposed to it for some time.
D Pesticides kill all the crops affected by insects, causing huge losses to farmers.

Answer 1

C

Repeated use of a pesticide can select for resistant insects, so over time the pesticide becomes less effective and stronger or different chemicals are needed, which raises costs and environmental/health risks.