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: Which animal eats only plants?  
 (A) Cat (B) Dog (C) Lion (D) Rabbit

SOLUTION: D

PROBLEM: Which of the following statements best explains how the decomposition of plant and animal matter helps to form rich soils?  
 (A) Decomposition adds silt to soil. (B) Decomposition adds water to soil. (C) Decomposition adds oxygen to soil. (D) Decomposition adds nutrients to soil.

SOLUTION: D

PROBLEM: When a predator feeding on certain prey is removed from the environment, which variable will most likely determine whether or not the prey will survive?  
 (A) temperature (B) available food (C) relative humidity (D) competition with other species

SOLUTION:
B