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.

The change in fur color of the Arctic hare from brown in the summer to white in the winter is an example of  
 (A) mimicry. (B) heredity. (C) diversity. (D) camouflage.
D

What happens when water flows over a rock for a long period of time?  
 (A) erosion (B) flooding (C) breakage (D) evaporation
A

Which tool is used to observe the cell wall of a leaf?  
 (A) ruler (B) camera (C) hand lens (D) microscope

D