Harming an animal species has a negative impact on the population size of that species.
Animals are harmed because of cosmetic testing.
Cosmetic testing has a negative impact on the population size of that species.
What has a negative impact on the population size of a species?
  * Pesticides
  * influenza
  * steroids
  * liver cancer
  * cloudy and rainy weather
  * massive damage
  * cosmetic testing
  * killing insects