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]: Melting, boiling, and freezing are examples of  
 (A) physical changes. (B) chemical changes. (C) magnetic changes. (D) electrical changes.
[A]: A


[Q]: The number of fish in a lake suddenly increases. How will the increase most likely affect the lake?  
 (A) There will be less water in the lake. (B) More plants will grow in the lake. (C) More frogs will live in the lake. (D) There will be fewer insects in the lake.
[A]: D


[Q]: Kelly slides a flat rock across the smooth ice of a frozen pond. The rock slows down after several seconds. What causes the rock to slow down?  
 (A) The thickness of the ice (B) The temperature of the air above the ice (C) The force of friction between the ice and the rock (D) The gravitational force between the ice and the rock
[A]:
C