Which of the following is the best example of natural selection? (1) A cheetah living in a zoo lives 10 years longer than average.
(2) The shell of a crab becomes harder over time as a result of being hunted by a predator.
(3) A person's muscles become firmer from riding a bike for exercise.
(4) A population of a rabbit's decreases in number as some move to another area.

A cheetah living in a zoo lives 10 years longer than average.

Explanation:

because Cheetahs living in captivity generally live a great deal longer than those in the wild, the life span of wild cheetahs is about 8 to 10 years, as opposed to 12 to 17 years for those in captivity according to the National Zoological Park, a sure fire sign of a healthy life.

(2)

Explanation:

Natural selection is the process in nature by which organisms better adapted to their environment tend to survive and reproduce more than those less adapted to their environment

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