You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Q: Which of these most likely determines if a mutation will become an adaptation in a species?  
 (A) genetic variation (B) mitosis (C) natural selection (D) succession

A: C
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Q: Several horses grazed in a fenced area across from a home. On rainy days, soil would wash down a slope and run toward the home. After the horses were moved a few years later, the soil no longer washed down when it rained. What could account for this change?  
 (A) The grass grew and kept the soil intact. (B) The fence kept the soil contained. (C) The soil was completely gone. (D) The amount of rain decreased.

A: A
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Q: Jeremiah noticed a plant had many missing leaves and large holes in other leaves. Why do missing leaves hurt the plant?  
 (A) The plant makes less food. (B) The plant takes in less water. (C) The plant attracts fewer insects. (D) The plant does not have support.

A:
A
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