Common step in aerobic and anaerobic respiration isSelect an answerAGlycolysisBKrebs cycleCFermentationDAll of these

Analysis of the Options

1. Glycolysis: This is the initial step in both aerobic and anaerobic respiration. It breaks down glucose into pyruvate, producing a small amount of ATP and NADH in the process. This step occurs in the cytoplasm.

2. Krebs Cycle: Also known as the citric acid cycle, this process occurs only in aerobic respiration. It oxidizes acetyl-CoA to produce carbon dioxide, ATP, NADH, and FADH₂.

3. Fermentation: This process occurs in anaerobic respiration. It is a way for cells to regenerate NAD⁺ under anaerobic conditions but does not involve the Krebs cycle.

4. All of these: This option suggests that all the listed processes are common to both types of respiration. However, since the Krebs cycle is exclusive to aerobic respiration, this choice cannot be correct.

Conclusion

The only common step in both aerobic and anaerobic respiration is glycolysis.

Final Answer

A. Glycolysis