Identifying roles in an ecosystem which organisms create all usable food energy on earth? consumers decomposers heterotrophs producers

Producers.

Explanation:

Producers are majorly green plants.

They produce food with the process of photosynthesis.

Photosynthesis is the process green plants produce food and oxygen by using light energy from the sun with carbondioxide and water.

The create all usable energy in the ecosystem. The consumers get their energy from them by feeding them and decomposers get energy on the consumers by acting or degrading them when they die.

"d.) carbon dioxide and hydrogen sulfide"