Fact 1: Poison causes harm to living things. Fact 2: Some plants are deadly poisonous . Given the two facts above, what causes harm to living things?

Available choices: [I] some plants; [II] Pesticides; [III] toxins; [IV] steroids; [V] cigarettes; [VI] fossil fuels; [VII] killing insects; [VIII] bacteria;
The answer is:
[I]