Answer:
It produces a net gain of ATP.
Explanation:
Glycolysis is a methabolic process that converts a glucose molecule (CβHββOβ) into two pyruvate molecules (CβHβOβ).
It has an energy investment phase when 2 ATP molecules are used, but later there is an energy payoff phase where 4 ATP molecules are produced, so there is a total net gain of 2 ATP. The electrons from glucose are used to reduce 2 NAD+ into 2 NADH.