Conclusion: Human beings can outlast many faster fourlegged animals when running long distances.

Premise/Explanation: Early humans evolved as hunters on the hot African savannas. Humans developed the ability to release heat by sweating, but most mammals must pant, a function hard to regulate while running. Also, four-legged animals must adopt a pace that lets them breathe once in mid-stride; otherwise, the impact of the front legs hitting the ground will prevent deep inhalation. Humans can vary the number of breaths per stride, set a pace unsuited to the prey. and so eventually exhaust it.

Question Type: Weaken the Argument

Prethinking: The best way to weaken the argument, given the facts, is to prove that the early humans evolved differently than stated OR the hunting habits of early humans did not involve long distance running.

Analyses of Choices:

(A) early humans typically hunted animals that were less well adapted than humans for long-distance running

This is a already stated in the argument and does nothing to weaken the argument.

(B) early humans were only one of a number of species that hunted prey on the African savannas

This does nothing to the argument.

(C) early humans hunted mainly in groups by sneaking up on prey and trapping it within a circle

This does it! It establishes that early humans did not run long distances to hunt their prey, thereby weakening the argument.

(D) hunting was just as essential for later humans in colder climates as it was for early humans on the African savannas

This does not say anything about the type of hunting or evolution of human beings. So it does not prove or disprove anything.

(E) human beings of today have retained the ability to run long distances but no longer hunt by chasing prey

This does not disprove the fact that they evolved as long distance runners.


So the answer is C