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.

[EX Q]: What is a decomposer?  
 (A) a living thing that breaks down dead organisms (B) a living thing that makes its own food (C) an animal that eats live plants (D) an animal that hunts other animals
[EX A]: A

[EX Q]: Earth is composed of layers of material with different properties. Which of the following is most likely to be in constant motion?  
 (A) core (B) mantle (C) oceanic crust (D) continental crust
[EX A]: B

[EX Q]: Wind can cause erosion that changes the surface of the Earth. Wind erosion can have negative effects on the environment by removing soil and polluting the air during dust storms. Which of the following land forms are created by wind erosion?  
 (A) arches and faults (B) sand dunes and arches (C) meanders and moraines (D) moraines and sand dunes
[EX A]:
B