Glycolysis and fermentation are thought to be older processes than the electron transport system and the Krebs cycle.

Answer

### Step-by-Step Solution:

1. **Understanding the Processes**:
- Glycolysis is the process of breaking down glucose into pyruvate, producing a small amount of ATP. It occurs in the cytoplasm and does not require oxygen (anaerobic).
- Fermentation is a metabolic process that converts sugars to acids, gases, or alcohol in the absence of oxygen. It follows glycolysis when oxygen is not available.

2. **Historical Context**:
- In the early stages of life on Earth, prokaryotic organisms (like bacteria) were the first forms of life. These organisms relied on anaerobic processes for energy production because the atmosphere lacked oxygen.
- Glycolysis and fermentation are both anaerobic processes and are thought to be some of the earliest methods of energy production.

3. **Aerobic Processes**:
- The electron transport system and the Krebs cycle are part of aerobic respiration, which requires oxygen. This process evolved later, after the development of mitochondria in eukaryotic cells.
- The presence of mitochondria allowed for more efficient energy production through aerobic respiration.

4. **Conclusion**:
- Since glycolysis and fermentation are older processes that evolved before aerobic respiration (electron transport system and Krebs cycle), the statement that "glycolysis and fermentation are thought to be older processes than the electron transport system and the Krebs cycle" is **true**.

### Final Answer:
The statement is **true**.

---