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.
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Question: In the United States, which is responsible for ensuring the safety of the country's drinking water?  
 (A) Environmental Protection Agency (EPA) (B) Food and Drug Administration (FDA) (C) National Oceanic and Atmospheric Administration (NOAA) (D) Center for Disease Control (CDC)

Answer: A


Question: Greenhouse gases in the atmosphere absorb infrared radiation from Earth's surface and re-radiates some of it back to Earth. Which of these gases have the most significant impact on the temperature of Earth's atmosphere?  
 (A) nitrogen and argon (B) oxygen and sulfur dioxide (C) carbon dioxide and water vapor (D) hydrochloric acid and hydrogen

Answer: C


Question: If your hands are cold, you can warm them by rubbing them together. The heat energy that you produce is caused by  
 (A) insulation. (B) magnetism. (C) friction. (D) conduction.

Answer:
C