Amino acid is to protein as what is to what?

Which beat describes the brain stem

10111213141516lactic acid fermentation differs from ethyl alcohol fermentation in thato in ethyl alcohol fermentation co2 is also producedlactic acid fermentation can occur in all living thingsethyl alcohol fermentation can only occur in plantsonly lactic acid fermentation can produce more atp

Sequence how oxygen accumulated in the atmosphere and the effect it had on life by completing the flowchart