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.

[EX Q]: In a northern state, a room used for growing plants is not allowing enough light to enter for healthy plant growth. Adding windows in walls facing which direction would best solve this problem?  
 (A) north (B) south (C) east (D) west
[EX A]: B

[EX Q]: Rock layers with sand-sized particles were most likely deposited by  
 (A) wind. (B) water. (C) glaciers. (D) landslides.
[EX A]: A

[EX Q]: There are many different types of living cells on Earth. Which of these characteristics do all living cells have in common?  
 (A) require water for survival (B) require silicon for structural support (C) require oxygen for respiration (D) require sunlight for photosynthesis
[EX A]:
A