Where does energy in an ecosystem come from?

Energy in an ecosystem comes from the Sun.

Explanation:

It is a major source of energy for organisms, plants and the whole ecosystem basically.

Most of the energy in an ecosystem comes from the sun, most producers such as plants, algae, etc. use the energy from the sun to create organic matter from carbon dioxide and water.

neutrons are in the middle of the atom and the electrons, which are much smaller.