What respiration requires no oxygen?

Anaerobic respiration is a type of respiration that does not require oxygen. In this process, organisms convert glucose into energy through fermentation or other pathways, resulting in byproducts like lactic acid or ethanol. Anaerobic respiration is commonly found in certain bacteria, yeast, and muscle cells during intense exercise when oxygen levels are low. This process is less efficient than aerobic respiration, producing only a fraction of the energy.