Harming an animal species has a negative impact on the population size of that species.
Small animals are harmed by pesticides.
Pesticides have a negative impact on the population size of a species.
What can have a negative impact on the population size of a species?
1: rainstorms
2: A virus
3: sexual reproduction
4: genetic diversity
5: deforestation
6: massive damage
7: Smoking
8: pesticides