Respuesta :
by Chemical reactions often involve changes in energy due to the breaking and formation of bonds. Reactions in which energy is released are exothermic reactions, while those that take in heat energy are endothermic.
Energy is used to start chemical reactions, such as photosynthesis. For example, light energy becomes converted into chemical energy during the process of photosynthesis, and chemical energy gets converted to ATP during cellular respiration. Hope this helps! :)