Which of the following best describes the fate of energy in ecosystems?

The fate of energy in ecosystems is for it to be lost as heat. Energy "flows" through the ecosystem in the form of carbon-carbon bonds. When respiration occurs, the carbon-carbon bonds are broken and the carbon is combined with oxygen to form carbon dioxide. This process releases the energy, which is either used by the organism (to move its muscles, digest food, excrete wastes, think, etc.) or the energy may be lost as heat. All energy comes from the sun, and that the ultimate fate of all energy in ecosystems is to be lost as heat.