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.

Example Input: Which of these elements is found in the greatest amount in organisms?  
 (A) carbon (B) iron (C) lead (D) neon
Example Output: A

Example Input: Which of the following best describes a role of mushrooms in ecosystems?  
 (A) capturing energy from sunlight (B) consuming living plant material (C) taking energy from animal hosts (D) breaking down dead plant material
Example Output: D

Example Input: Kendall studied the ways in which human body systems work together. He compared the respiratory and circulatory systems. In which way are these two systems similar to each other?  
 (A) They both bring oxygen to the body. (B) They both send messages to the body. (C) They both digest nutrients for the body. (D) They both pump blood through the body.
Example Output:
A