TASK DEFINITION: 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.
PROBLEM: Why should plants be included in investigations about the water cycle?  
 (A) Plants speed up the water cycle by removing carbon from the air. (B) Plants start the water cycle when they make water in photosynthesis. (C) Plants are part of the water cycle through the process of transpiration. (D) Plants stop the water cycle because they absorb it and stop the flow to streams.

SOLUTION: C

PROBLEM: Solar radiation provides more heat near the equator than near the poles on Earth. The greatest amount of heat is moved away from the equator by  
 (A) ocean currents. (B) aquatic plants. (C) surface winds. (D) tectonic plates.

SOLUTION: A

PROBLEM: When a small group of organisms colonizes a new habitat, the population may be genetically different from the parent population due to differences in allele frequencies. The process responsible for this is  
 (A) natural selection. (B) disruptive selection. (C) genetic drift. (D) genetic equilibrium.

SOLUTION:
C