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.

[Q]: Elephants on the African savanna eat shrubs and small trees. This behavior clears land and enables grass to grow. Grazers such as gazelles eat the grass. Lions prey on the gazelles. Which two organisms in this scenario are in the most cooperative relationship?   
 (A) the elephants and the shrubs (B) the shrubs and the lions (C) the elephants and the gazelles (D) the gazelles and the lions
[A]: C


[Q]: Amanda and Jake learned about kinetic and potential forms of energy within a simple electrical circuit. The circuit they are studying has a battery, wires, and a light bulb. Which is a form of potential energy in the circuit?  
 (A) chemical energy in the battery (B) light energy from the light bulb (C) heat energy lost from the electric wires (D) electrical energy moving through the light bulb
[A]: A


[Q]: When a mixture of oxygen and hydrogen is ignited in a test tube, the reaction shown occurs. Hydrogen + Oxygen -> Water + Energy What happens to the total mass of the contents of the test tube?  
 (A) The total mass increases. (B) The total mass decreases. (C) The total mass remains the same. (D) Part of the mass is changed to heat energy.
[A]:
C