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: Different units of measurement are more useful in some settings than in others. Which unit of measurement is most used when comparing distances within the solar system?  
 (A) the mile (B) the kilometer (C) the light year (D) the astronomical unit

SOLUTION: D

PROBLEM: It rained on a hot summer afternoon and a puddle formed. After several hours, the puddle was gone. Which two processes made the puddle form and then disappear?  
 (A) precipitation followed by evaporation (B) deposition followed by evaporation (C) precipitation followed by runoff (D) deposition followed by runoff

SOLUTION:
A