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

A: A
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Q: Which process in the water cycle returns water from the surface of Earth to the atmosphere?  
 (A) condensation (B) evaporation (C) precipitation (D) runoff

A: B
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Q: Which property of an object is identified using the sense of smell?  
 (A) color (B) odor (C) temperature (D) weight

A:
B
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