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In the desert biome the temperature's are extreme, they could get to over 100 degrees. Plants and animals adapted to their environment over many centuries. The amount of precipitation a plant or animal get can effect how they grow, plants need lots of water so the can grow.

Explanation:

there is an explationation of this on a site called crash   course world history 1

answer; i believe the correct answer is (a) the correlation between the cause variable and outcome variable is zero;