What is Acetyl-coA and how does it help with food digestion ?

what is Acetyl CoA is made from pyruvate under aerobic conditions in the mitochondria. The process of conversion is irreversible. I don't know the other half I'm sorry.

Explanation:

Acetyl CoA Used by the citric acid cycle as a fuel. Carbon acetyl groups are converted to CO2 and ATP and electrons (carried by NADH and FADH2) create even MORE electrons.  Acetyl CoA is made from pyruvate under aerobic conditions in the mitochondria. The Process of conversion is irreversible.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.