instruction:
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.
question:
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
answer:
A


question:
Which two protein molecules are essential for muscle contraction and relaxation?  
 (A) actin and myosin (B) collagen and tubulin (C) hemoglobin and myoglobin (D) amylase and polymerase
answer:
A


question:
Which seismic wave phenomenon, found at structural boundaries, allows scientists to interpret the interior structure of Earth?  
 (A) refraction of waves (B) generation of new waves (C) transformation of transverse waves into longitudinal waves (D) transformation of mechanical waves into electromagnetic waves
answer:

A