OPTIONS: 1. omnivores. 2. harmed. 3. deadly. 4. dead. 5. haploid. 6. negative. 7. dormant. 8. inactive.
Q: Fact 1: Harming an animal species causes that animal 's population to decrease. Fact 2: Ecology is the study of populations or communities. Given the two facts above, ecology studies something that decreases when an animal species is what?
A:
2.