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: Some people carry a mutated allele of a particular gene that makes them resistant to HIV infection and AIDS. Which best describes this type of mutation?  
 (A) beneficial (B) asexual (C) harmful (D) unicellular

A: A
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Q: Which unit of measurement describes an object's length?  
 (A) meter (B) kilogram (C) liter (D) degree

A: A
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Q: Miranda's neighbors have an apple tree in their yard. What is the source of energy for the apple tree?  
 (A) rain (B) soil (C) sunlight (D) wind

A:
C
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