Final answer:
Glycolysis is the energy-generating process that occurs in all living organisms. It is an anaerobic process conserved across all domains of life and does not depend on oxygen.
Step-by-step explanation:
The energy-generating process that occurs in all living organisms is glycolysis. Glycolysis is a universal metabolic pathway present in all forms of life, from bacteria to archaea to eukaryotes. It is an anaerobic process that takes place in the cytoplasm and begins the breakdown of glucose, ending with the formation of pyruvate.
Glycolysis is an ancient metabolic process, suggesting its importance and conservation throughout evolution. Despite the existence of other energy-generating processes like the Krebs cycle or photophosphorylation, glycolysis is the most fundamentally pervasive system, and it does not depend on oxygen for its execution, making it essential for both aerobic and anaerobic organisms.
Therefore, the correct answer to the question is: a) glycolysis.