You are presented with the question "What has a negative impact on a species population size?" and the following answer choices: 
- influenza
 - assistance
 - pollution
 - distractions
 - liver cancer
 - copper
 - Pesticides
 - disease

Now knowing that harming an animal species has a negative impact on the population size of that species and people understand that habitat destruction and pollution are harmful to wildlife, choose the best answer.


 

   pollution      