Cellular respiration is a vital process that occurs in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. Of the options provided, the one essential for cellular respiration is b) oxygen.
Oxygen plays a crucial role in aerobic respiration, which is the process in which cells use oxygen to help convert glucose into energy (ATP). During this process, glucose is broken down in the presence of oxygen, resulting in carbon dioxide and water as byproducts. Without oxygen, the cells cannot efficiently produce ATP through aerobic respiration, leading them to rely on anaerobic processes that generate less energy. Thus, oxygen is indispensable for the effective production of energy in most organisms.