What cellular process releases energy by breaking down glucose when oxygen is not available
a. aerobic respiration
b. the calvin cycle
c. photosynthesis
d. anaerobic respiration

d. Anaerobic Respiration

Explanation:

Living cells require energy to perform their various life functions. This energy is obtained by breaking down high energy storing food molecules in a process called CELLULAR RESPIRATION. Cellular respiration is a metabolic (catabolic) process that breaks down glucose to release carbondioxide, water and ATP (energy).

Cellular respiration can either be aerobic or anaerobic depending on whether oxygen is present or not. Aerobic respiration occurs in the presence of oxygen while anaerobic respiration occurs in the absence of oxygen. In the process of aerobic cellular respiration, Oxygen acts as a final electron acceptor in the ETC while in anaerobic respiration, another molecule other than oxygen e.g Sulfur acts as the final electron acceptor.

Some bacteria and yeast employs anaerobic respiration.

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).