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.
--------
Question: 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

Answer: B


Question: Marta studied different forms of energy. Which two types of energy travel in waves?  
 (A) light and sound (B) electrical and sound (C) chemical and light (D) chemical and electrical

Answer: A


Question: Humans depend on which natural resource from the environment?  
 (A) water (B) houses (C) electricity (D) roads

Answer:
A