Why does a rubber band become warm when you stretch it repeatedly

A rubbber band becomes warm when stretched repeatedly because it stores its energy as thermal energy. When you stretch the rubber band again and again, this gives the rubber more thermal energy, causing it to heat up.

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.