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 Sun is classified as  
 (A) an organism (B) a decomposer (C) a star (D) a planet

A: C
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Q: The basic life functions of an organism are carried on by  
 (A) cells (B) nutrients (C) atoms (D) hormones

A: A
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Q: A scientist combines oxygen and hydrogen to form water. This combination illustrates that water is  
 (A) an atom. (B) an element. (C) a mixture. (D) a compound.

A:
D
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