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.

[EX Q]: Why should plants be included in investigations about the water cycle?  
 (A) Plants speed up the water cycle by removing carbon from the air. (B) Plants start the water cycle when they make water in photosynthesis. (C) Plants are part of the water cycle through the process of transpiration. (D) Plants stop the water cycle because they absorb it and stop the flow to streams.
[EX A]: C

[EX Q]: One method of heat distribution is a baseboard forced hot water system. A baseboard system carries hot water through a pipe that passes through many small, flat plates called fins. What is the purpose of these fins?  
 (A) to dissipate the heat of the hot water flowing through the pipe (B) to prevent the baseboard from coming in contact with hot surfaces (C) to replace the heated air leaving the system with cold air (D) to prevent dust and other particles from entering the baseboard
[EX A]: A

[EX Q]: About how often is a full moon observed from Earth's surface?  
 (A) each week (B) once a month (C) every two weeks (D) once each leap year
[EX A]:
B