At the time of aerobic respiration, the oxygen is taken up by the cells and in combination with glucose generates energy in the form of ATP, and the cell expels water and carbon dioxide. This is an oxidation-reduction reaction in which glucose is oxidized and oxygen is reduced.
In the entire process of oxidation, glucose is losing one or more electrons to oxygen, and in reduction, oxygen is gaining electrons.
Thus, the correct answer is glucose is losing those electrons through oxidation and oxygen gains those electrons through the process of reduction.