Because fermentation does not require oxygen it is said to be

Anaerobic

Explanation:

Cellular respiration involves the breakdown of glucose to produce energy in the form of ATP and other by-products such as water and carbon dioxide. Cellular respiration can be classified as anaerobic or aerobic respiration. Aerobic respiration is a type of respiration that occurs in the presence of oxygen gas and produces energy in the form of ATP, carbon dioxide and water. Anaerobic respiration, on the other hand, occurs in the absence of oxygen to produce a minimal amount of energy and also form alcohol or lactic acid as byproducts. Fermentation is said to anaerobic since it occurs in the absence of oxygen.