Q: Fact 1: Poison causes harm to living things. Fact 2: Toxins or poisons are a stress. Given the two facts above, _causes harm to living things?

OPTIONS:
[i] Nematoda
[ii] organisms
[iii] stress
[iv] pesticide
[v] nutrients
[vi] stimuli
[vii] animals
[viii] moisture
A:
[iii]