Answer: False
Explanation:
Protozoans are not the organism that fix nitrogen for the plants. The organism that fix nitrogen to convert it into a form which can be used by plants are known as diazotrophs.
These are bacteria and archae that fix nitrogen gas found in the atmosphere into more usable form such as ammonia.
These organism can grow without any external source of fixed nitrogen. Example: Rhizobia and azospirillium.
Fatty acids only
Acetyl coenzyme A is a biological molecule that is used in biochemical reactions. These biochemical reactions include the breakdown or hydrolysis of protein, carbohydrates and lipid molecules. The hydrolysis of these molecules in the presence of acetyl CoA produces energy and its primary function is fatty acid metabolism.
Answer is D bra, I just guessed and got it right.
It was the plants around us. They give us air to breath. It was to help us breath so we can live.