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.

[Q]: What is the downward movement of water through pores and other spaces in soil due to the force of gravity?  
 (A) percolation (B) evaporation (C) precipitation (D) condensation
[A]: A


[Q]: One substance found on Earth is more stable as an elemental gas than as part of a solid compound. As a result, this substance is very abundant in the atmosphere. Which substance exhibits these traits?  
 (A) argon (B) chlorine (C) nitrogen (D) oxygen
[A]: C


[Q]: Which part of a plant is most responsible for using energy from the Sun to produce food for the plant?  
 (A) flower (B) leaf (C) root (D) stem
[A]:
B