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 action involving a pulley system requires the least amount of force?
(A) using several pulleys together instead of a single pulley (B) using a fixed pulley instead of a moveable pulley (C) pulling a long rope instead of a short rope (D) pulling a rope up instead of down

A: A
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Q: Air is composed of many different substances. Which of the following components of air is a compound rather than an element?
(A) Argon, Ar (B) Oxygen, O2 (C) Water, H2O (D) Nitrogen, N2

A: C
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Q: Which of the following statements best describes photosynthesis?
(A) Carbon dioxide and water are turned into sugar and oxygen. (B) Sugar and oxygen are turned into water and carbon dioxide. (C) Oxygen and carbon dioxide are turned into water and sugar. (D) Water and sugar are turned into oxygen and carbon dioxide.

A:
A
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