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: When sodium hydroxide reacts with a copper nitrate solution, the reaction vessel needs to be kept on ice to slow down the reaction. What best describes this reaction?
(A) an exothermic reaction that absorbs energy (B) an exothermic reaction that releases energy (C) an endothermic reaction that absorbs energy (D) an endothermic reaction that releases energy

SOLUTION: B

PROBLEM: Which of the following is the best example of potential energy?
(A) a fallen rock (B) a burning match (C) a liter of gasoline (D) a red-hot piece of iron

SOLUTION: C

PROBLEM: The empty spaces in a material are called pores. Porosity is the amount of empty space within a material. Permeability describes how well the pores in a material are connected. Which of these materials would make the most effective aquifer?
(A) a material that has high porosity and high permeability (B) a material that has high porosity and low permeability (C) a material that has low porosity and high permeability (D) a material that has low porosity and low permeability

SOLUTION:
A