The pyramid of energy is always upright.

Answer

### Step-by-Step Solution:

1. **Understanding the Pyramid of Energy**:
- The pyramid of energy represents the flow of energy through different trophic levels in an ecosystem. It illustrates how energy is transferred from producers (like plants) to various levels of consumers (herbivores, carnivores, etc.).

2. **The 10% Law**:
- According to the 10% law, only about 10% of the energy from one trophic level is transferred to the next level. The remaining 90% of energy is lost primarily as heat due to metabolic processes.

3. **Unidirectional Flow of Energy**:
- Energy flow in an ecosystem is unidirectional, meaning it moves in one direction—from producers to consumers. This indicates that energy does not flow back to the producers from the consumers.

4. **Upright vs. Inverted Pyramid**:
- An upright pyramid of energy means that as you move up the trophic levels, the amount of energy decreases. In contrast, an inverted pyramid would suggest that there is more energy at higher trophic levels than at lower ones, which is not the case in a typical ecosystem.

5. **Conclusion**:
- Since energy flows from producers to consumers in a unidirectional manner and only a small fraction (10%) is transferred to the next level, the pyramid of energy is always upright. Therefore, the statement "The pyramid of energy is always upright" is true.

### Final Answer:
The statement is true: The pyramid of energy is always upright.

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