A strawberry farmer finds that, after a hard freeze, some of his strawberries are still alive. Which best explains why these stran were able to survive?
A. They have larger leaves to protect the fruit than the other strawberries.
B. They have different genetic variations that cause them to be more resistant to cold temperatures.
C. They are able to reproduce more quickly than the other strawberries.
D. The color of the strawberries is darker, and they maintain their temperature better than other strawberries.

B. They have different genetic variations that cause them to be more resistant

Explanation:

We do not know the phenotype of the strawberries and cannot tell if they have a darker color or larger leaves so that eliminates A. and D. We also do not know which strawberries produce faster or if the strawberries are even a different type than the ones the froze so that eliminates C. But what we do know is that variation is key to survival and variation means some organisms might not be able to resist certain things others can.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."