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: The Piedmont and Coastal Plains regions in Maryland produce crops such as corn, soybeans, wheat, tobacco, tomatoes, and apples. Which environmental factor most likely influences which crops are grown in these regions?  
 (A) soil quality (B) wind speeds (C) bird migration (D) water temperature

A: A
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Q: Which type of organism is the best at fixing nitrogen?  
 (A) bacteria (B) fungi (C) protists (D) animals

A: A
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Q: Aphids are small insects that sometimes live near ants. The ants protect the aphids from predators. The aphids produce a sweet substance that the ants eat. Which statement describes the relationship between ants and aphids?  
 (A) Both ants and aphids benefit. (B) Both ants and aphids are unaffected. (C) The ants benefit and the aphids are harmed. (D) The aphids benefit and the ants are unaffected.

A:
A
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