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]: The Grand Canyon is an example of  
 (A) erosion. (B) deposition. (C) an earthquake. (D) volcanic activity.
[EX A]: A

[EX Q]: All of the following can become fossils except  
 (A) bones. (B) shells. (C) teeth. (D) rocks.
[EX A]: D

[EX Q]: Where do many of the basic life functions take place in organisms?  
 (A) brain (B) cells (C) heart (D) nerves
[EX A]:
B