Is oxygen a product of cellular respiration?

Microorganisms aren’t all decomposers; in fact, many act as producers or primary consumers in an ecosystem. how do microorganisms that act as producers benefit the rest of an ecosystem in terms of energy transfer? what about microorganisms that act as primary consumers?

Which experiment would most likely contain experimental bias ?

How does buring fossil fuels impact does carbon cycle? what large impact does this have on the envirnment?