Mashaal Masha
Many animals, including humans, must sleep, and sleep is known to have a role in everything from healing injuries to encoding information in long-term memory. But some scientists claim that, from an evolutionary standpoint, deep sleep for hours at a time leaves an animal so vulnerable that the known benefits of sleeping seem insufficient to explain why it became so widespread in the animal kingdom. These scientists therefore imply that __________

Which choice most logically completes the text?
Difficulty: Hard
A: 

prolonged deep sleep is likely advantageous in ways that have yet to be discovered.

B: 

most traits perform functions that are hard to understand from an evolutionary standpoint.

C: 

it is more important to understand how widespread prolonged deep sleep is than to understand its function.

D: 

many traits that provide significant benefits for an animal also likely pose risks to that animal.

Sponsored AdsHide Ads