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.

The greatest amount of diversity can be found among which type of organism?  
 (A) plants (B) animals (C) bacteria (D) fungi
C

Electron transport in mitochondria results in a chemiosmotic gradient of which particle across the mitochondrial membrane?  
 (A) ADP (B) ATP (C) protons (D) neutrons
C

Isabel goes jogging for two miles on a sunny afternoon. At the end of her run, she is warmer. As Isabel jogs, which function does the skin perform to help stabilize her body temperature?  
 (A) Her skin exchanges oxygen and carbon dioxide. (B) Her skin produces red blood cells. (C) Her skin releases hormones. (D) Her skin discharges water.

D