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: A population of plants growing on an island consisted of two varieties, one with thorns and the other without. Over a period of many years, the variety with thorns gradually disappeared. Which process most likely brought about this change in the plant population?  
 (A) gene flow (B) genetic drift (C) natural selection (D) random mutation

A: C
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Q: There is a river at the base of Mount Tom. In the spring the water level is usually very high. In the summer it is lower. The higher level of water during the spring comes from  
 (A) hurricanes. (B) melting snow. (C) tornadoes. (D) evaporating water.

A: B
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Q: Which sequence has the states of matter listed from least to greatest kinetic energy?  
 (A) solid -> gas -> liquid (B) gas -> liquid -> solid (C) liquid -> solid -> gas (D) solid -> liquid -> gas

A:
D
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