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: Which of these cycles takes 24 hours?  
 (A) Earth rotating on its axis (B) Earth revolving around the Sun (C) the Moon rotating on its axis (D) the Moon revolving around Earth

SOLUTION: A

PROBLEM: Auroras occur where Earth's magnetosphere traps high-energy particles in which region of the atmosphere?  
 (A) troposphere (B) stratosphere (C) thermosphere (D) exosphere

SOLUTION: C

PROBLEM: If an ecosystem's balance is disturbed by a volcanic eruption, what will most likely occur?  
 (A) The ecosystem will not change from its original state. (B) The ecosystem will eventually become balanced again. (C) The consumers in the ecosystem will begin to consume carbon dioxide. (D) The consumers in the ecosystem will begin to produce more oxygen.

SOLUTION:
B