Please answer the following question: Fact 1: Harming an animal species has a negative impact on the population size of that species. Fact 2: People understand that habitat destruction and pollution are harmful to wildlife. Given the two facts above, answer the question "What has a negative impact on a species population size?" with the following options: - influenza - assistance - pollution - distractions - liver cancer - copper - Pesticides - disease
A:
pollution