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 teacher heats a pot of water. Once the water reaches 100°C, which point has the water reached?  
 (A) boiling (B) melting (C) freezing (D) evaporating
[EX A]: A

[EX Q]: Which of the following helps the body to cool down?  
 (A) shivering (B) sweating (C) running a fever (D) taking deep breaths
[EX A]: B

[EX Q]: Which scientist would be most likely to study the changes in animal populations in nature?  
 (A) Botanist (B) Engineer (C) Ecologist (D) Veterinarian
[EX A]:
C