Answer:
a. toxic to insects is the correct answer.
Explanation:
- Toxic to insects is not a negative impact of pesticide use.
- The pesticide is used as a toxin against the insects,
- It is used to control the insect's infestation and to kill the insects.which is not negative because we need to eliminate insects to control insect infection, diseases and to protect the crops from the insect.
- The other three options have negative effects caused due to the use of pesticides.
