You are given a science question (easy-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: Bones support the body. What pulls and pushes on bones to move them?  
 (A) blood (B) nerves (C) muscles (D) skin

A: C
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Q: Some scientists have suggested that the Moon was formed when a large body struck Earth and broke off a piece of Earth billions of years ago. Which observation would best support this suggestion?  
 (A) The rocks of the Moon are older than Earth rocks. (B) The Earth has free standing water, but the Moon does not. (C) The Earth and the Moon are gravitationally locked together. (D) The chemical composition of Moon rocks is similar to Earth rocks.

A: D
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Q: In the 1970s, the pesticide DDT was used to kill insects that damaged fruit and vegetable crops. Most insects died from being exposed to DDT, but some survived. These surviving insects contributed to an increase in their population by  
 (A) migrating to habitats that had different types of crops. (B) learning how to avoid being exposed to DDT. (C) passing the gene for DDT resistance to their offspring. (D) competing with other types of insects for food.

A:
C
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