Let's say you use a 1-foot basketball to represent the Sun and a pea to represent the Earth. About how far must they be placed apart to represent an accurate scale of the Sun to the Earth?

When someone eats food

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.