During decomposition, high-energy organic molecules from the bodies of plants and animals are converted to molecules such as carbon dioxide and water, which are

During decomposition, high-energy organic molecules from the bodies of plants and animals are converted to molecules such as carbon dioxide and water, which are used by plants as  raw materials for the photosynthesis that is used by plants to make food. Carbon dioxide produced is released to the atmosphere where plants use is in photosynthesis, while water is absorbed by the plants through the roots and used in the same process. Decomposers are organisms such as bacteria and fungi that change wastes and dead organisms into usable nutrients which are then made available to other organisms.

 the answer is
Low energy