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

it's the cell cycle, but cytokines is when the cell divides.

theres 3 stages interphase,mitosis,and cytokines.

interphase prepares the cell for division.

mitosis is the process of dividing the cell,it has 4 parts interphase,anaphase,metaphase,and telophase.

lastly there's cytokines,that's when the cell divides into 2 daughter cells