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: Use of nuclear fuel would most likely reduce human contributions to which environmental problem?  
 (A) ozone thinning (B) landfill creation (C) shoreline erosion (D) greenhouse heating

A: D
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Q: Which best explains how nutrients get into soil?  
 (A) through exposure to air (B) by absorbing sunlight (C) through decaying matter (D) by rocks eroding

A: C
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Q: In humans, the amount of sugar in blood is controlled by the release of a hormone called insulin. This process is an example of  
 (A) depletion (B) digestion (C) regulation (D) excretion

A:
C
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