TASK DEFINITION: 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.
PROBLEM: Compost piles have many parts, such as leaves, moisture, vegetables, and microorganisms. Which part of a compost pile breaks down materials and adds nutrients to the soil?  
 (A) leaves (B) moisture (C) vegetables (D) microorganisms

SOLUTION: D

PROBLEM: Which two behaviors best demonstrate stewardship?  
 (A) reducing consumption, recycling wastes (B) increasing consumption, discarding wastes (C) reducing consumption, discarding wastes (D) increasing consumption, recycling wastes

SOLUTION: A

PROBLEM: Planets outside of our solar system have been detected. What suggested the presence of a planet outside of our solar system?  
 (A) radio wave emissions (B) a wobble in the rotation of the star (C) regular occurring eclipses of its moons (D) the discovery of a star as large as our own

SOLUTION:
B