Part 1. Definition
You are given a science question (hard-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.
Part 2. Example
Which event can cause a large rock to become soil over time? 
 (A) decaying (B) an earthquake (C) a landslide (D) weathering
Answer: D
Explanation: Under the action of heat, cold, rain, wind, and other atmospheric factors, the rock breaks down physically into small fragments that become the parent material of the soil. Also, atmospheric factors change according to weather.
Part 3. Exercise
Newton's first law of motion states that an object at rest will stay at rest unless acted upon by an outside force. Which activity is an example of this law?  
 (A) A football is kicked off a tee. (B) A baseball player slides into second base. (C) A floating stick is carried over a waterfall. (D) A bicycle travels faster as it goes downhill.
Answer:
A