The breakdown of food molecules, such as glucose in the absence of oxygen is called?

If oxygen is present, then glucose can be broken all the way down into carbon dioxide and water. This process is called aerobic respiration because it requires air (oxygen). In the absence of oxygen, the cell uses a process called anaerobic fermentation. or simply fermentation.

The complete glucose breakdown is a series of chemical reactions representing transformation of glucose to adenosine triphosphate during the normal phases of aerobic cellular respiration. It is mostly done inside the mitochondria to release the maximum amount of energy.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).