Problem:

Question 1: Explain why dramatic climate change in the African Rift Valley affected human evolution, particularly as pertained to hairlessness, brain size or hairlessness.

Question 2: Explain why differences in skin pigmentation in human populations can be explained by the theory of evolution and natural selection.

Question 3: Why the theory of natural selection can explain why harmful mutations that cause diseases like cystic fibrosis or sickle cells anemia are not removed from human populations?

Question 4: Imagine what would have happened if the first humans in Africa developed a mutation that allowed them to make vitamin D without sunlight. What effect would that have had on skin color in modern humans across the world?(In the answer, it need explain in terms of natural selection why your prediction of what human would look like makes sense.)

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