instruction:
You are given a science question (hard-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:
Cells take in food for energy. The part of the cell that aids in digestion of the food is the lysosome. What is the main role of lysosomes in the process of food digestion?  
 (A) building proteins (B) breaking down wastes (C) controlling the activities of the cell (D) converting energy from one form into another
answer:
B


question:
Which layer of Earth is the source of lava that erupts from volcanoes?  
 (A) asthenosphere (B) inner core (C) outer core (D) lithosphere
answer:
A


question:
Which event is the best example of mechanical energy?  
 (A) wood burning (B) light shining (C) a song playing on a radio (D) a wagon rolling down a hill
answer:

D