The first stage of cellular respiration is glycolysis. It does not require oxygen. During glycolysis, one glucose molecule is split into two pyruvate molecules, using 2 ATP while producing 4 ATP and 2 NADH molecules.
This can be identified as a population. In a population, the organisms are the same species and they have to live in the same area. For example, the population of cities are the head count of the species of human in that one area.
Viruses, bacteria, fungus,Protozoa and worms