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 these will best separate a saltwater solution?  
 (A) using a paper filtering system (B) using chromatography (C) allowing the salt to settle (D) allowing the water to evaporate

A: D
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Q: Which physical structure would best help a bear to survive a winter in New York State?  
 (A) big ears (B) black nose (C) thick fur (D) brown eyes

A: C
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Q: Which situation is an example of a feedback system in the body that maintains homeostasis?  
 (A) a mouse pushing a lever to release food (B) a dog going to a food bowl when a bell rings (C) students receiving star stickers for good behavior (D) the brain signaling blood vessels to return to normal

A:
D
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