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: Which of the following best describes a mineral?  
 (A) a solid natural material with a crystal structure (B) a material that was once living but has decayed (C) a liquid chemical used to make soil more fertile (D) a nutrient produced by plants that other organisms need

A: A
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Q: During which season of the year would a rabbit's fur be thickest?  
 (A) fall (B) spring (C) summer (D) winter

A: D
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Q: In a forest ecosystem, the squirrels eat seeds from trees. The squirrels are then eaten by hawks, owls, and foxes. If there were no more owls present in this ecosystem, which would most likely happen in the forest?  
 (A) The squirrel population would increase. (B) The hawk population would decrease. (C) The fox population would decrease. (D) The tree population would increase.

A:
A
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