Glycolysis is linked to the Krebs cycle when oxygen is not available.

Answer

**Step-by-Step Solution:**

1. **Understanding Glycolysis**: Glycolysis is the first step in the breakdown of glucose to extract energy. It occurs in the cytoplasm and converts one molecule of glucose into two molecules of pyruvate, producing a small amount of ATP and NADH in the process.

2. **Role of Oxygen in Cellular Respiration**: Oxygen is crucial for aerobic respiration, which includes the Krebs cycle (also known as the citric acid cycle or TCA cycle). The Krebs cycle occurs in the mitochondria and requires oxygen to proceed.

3. **Link between Glycolysis and Krebs Cycle**: Under normal aerobic conditions, the pyruvate produced from glycolysis is transported into the mitochondria, where it enters the Krebs cycle for further oxidation, leading to the production of more ATP.

4. **What Happens When Oxygen is Not Available**: In the absence of oxygen, the process shifts from aerobic respiration to anaerobic processes. Instead of entering the Krebs cycle, pyruvate undergoes fermentation. This process does not require oxygen and results in the production of either lactic acid (in animals) or ethanol and carbon dioxide (in yeast).

5. **Conclusion**: Therefore, the statement "Glycolysis is linked to the Krebs cycle when oxygen is not available" is false. The correct statement is that glycolysis is linked to the Krebs cycle when oxygen is available.

**Final Answer**: The statement is false.

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