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.

Which is the best example of something that has kinetic energy?
(A) a rock sitting at the top of a steep hill (B) a tennis ball rolling across the court (C) a picture hanging on the wall (D) a piece of wood before it is burned
B

Amylase is a chemical that decomposes starch into maltose and dextrin. Which best describes the role of amylase in the human body?
(A) as an inhibitor of insulin production (B) as an enzyme that aids in digestion (C) as a catalyst for protein synthesis (D) as a receptor of fatty acid chains
B

The statement "gold is more dense than lead" is
(A) a fact because most people agree. (B) a fact because it has been observed and tested. (C) an opinion because both metals are hard to find. (D) an opinion because more research is needed.
B