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


[Q]: Which body systems are most involved in the response when someone stubs his or her toe?  
 (A) nervous and muscle (B) muscle and endocrine (C) nervous and digestive (D) reproductive and circulatory
[A]: A


[Q]: The fossil record shows that trees have changed throughout the years. Which of the following conclusions would be best supported by the fossil record?  
 (A) The environment has changed. (B) Animals need leafy trees. (C) Rocks can destroy trees. (D) Trees give off oxygen.
[A]:
A