18. Which of the following would be an example of an animal being in the lower limit
of tolerance?
a. A shark in warm water.
b. A bird in a tree that has everything it needs.
C. A frog being in water that is too cold to maintain homeostasis.
d. None of the above

I think it would be A.

Organisms with the most favourable traits will increase their success rate in a particular environment. Organisms with favorable traits are more likely to reproduce and pass on their traits than organisms without favorable traits, allowing it to survive.