Fact 1: Harming an animal species has a negative impact on the population size of that species.

Fact 2: Animals are harmed because of cosmetic testing.

Given the two facts above, answer the question "What has a negative impact on the population size of a species?" with the following options: 
- Pesticides
 - influenza
 - steroids
 - liver cancer
 - cloudy and rainy weather
 - massive damage
 - cosmetic testing
 - killing insects


 

       cosmetic testing  