Glycolysis occurs in the ________ and produces________, which in the presence of ${\mathrm{O}}_2$ enters the____________.

Glycolysis occurs in the cytoplasm and does not use oxygen. Thus, it is an anaerobic pathway. In this process, glucose is partially oxidized/converted into two molecules of pyruvate/ pyruvic acid. In aerobic respiration pyruvate enters mitochondrion through a specific transport protein. It undergoes oxidative decarboxylation and dehydrogenation to produce ${\mathrm{CO}}_2$ and NADH.