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.

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)
A

What determines how long the Moon takes to complete one cycle of phases?  
 (A) the period of rotation of the Moon around its axis (B) the period of revolution of the Moon around Earth (C) the period of rotation of Earth around its axis (D) the period of revolution of Earth around the Sun
B

Nutrients enter the bloodstream during the process of  
 (A) locomotion (B) respiration (C) elimination (D) absorption

D