Fact 1: Poison causes harm to living things.

Fact 2: Most of the snakes that live in swamps are poisonous.

Given the two facts above, answer the question "what causes harm to living things?" with the following options: 
- snakes
 - cats
 - toxins
 - mice
 - plants
 - HIV
 - pesticide
 - parasites


 

 snakes        