Where does an ecosystem’s energy originally come from ?

from the sun

Explanation: Energy enters the ecosystem from the Sunand exits after the organisms have taken as much as they need. Organisms release energy back into the biosphereas heat. Energy also enters the ecosystem from the interior of the Earth. It is usually in the form of heat, not the electromagnetic radiation from the Sun.

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.