Answer:
1.The first hypothesis is that blindness gives the tetra some sort of evolutionary advantage. That advantage might be the result of pleiotropy, which is when multiple effects are caused by the same mutation in one gene. Scientists think that the mutation that causes blindness in the tetra might also cause a "seemingly unrelated change in the fish that is beneficial."
2. Another effect it might have is to improve cave tetras' sense of smell.
Explanation:
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