By sharing electeons with each other
if they lose or gain electrons then they only form ions
they cannot lose neutrons as they are locked inside the nucleus
The given question is incomplete. The image present in the question for Reaction A is attached below along with the answer.
Explanation:
Pyruvate molecule reacts with Coenzyme A in the presence of oxygen and it results in the formation of acetyl Coenzyme A and carbon dioxide.
The enzyme pyruvae dehydrogenase helps in catalyzing this reaction. As in this biochemical reaction
gets converted into NADH.
This reaction is shown in the image attached below.
I believe it is b. you only want to change one thing at a time so you know which one thing caused the effect