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: The Grand Canyon is an example of  
 (A) erosion. (B) deposition. (C) an earthquake. (D) volcanic activity.

SOLUTION: A

PROBLEM: One hot summer, a grassland experienced a drought. Which most likely happened in the ecosystem during this time?  
 (A) The competition for food among primary consumers increased. (B) Nutrients cycled through the system at a faster rate. (C) Less solar radiation was able to enter the system. (D) Secondary consumers became extinct.

SOLUTION: A

PROBLEM: When you bend your arm at the elbow, the bones and muscles in your arm are acting as a system. What simple machine does this system represent?  
 (A) Inclined plane (B) Pulley (C) Wedge (D) Lever

SOLUTION:
D