Available options:
[I] bears.
[II] bacteria.
[III] pigeons.
[IV] humans.
[V] tigers.
[VI] rocks.
[VII] Mammal.
[VIII] hats.

Fact 1: Better senses have a positive impact on an animal 's survival. Fact 2: Bears are curious animals. Given the two facts above, better senses can have a positive impact on the survival of what?
Answer:
[I]