Which of the following pyramids is always upright and can never be inverted ?

Options

A. Pyramid of biomass
B. Pyramid of numbers
C. Pyramid of energy
D. Both (a) and (c)

Answer

To solve the question "Which of the following pyramids is always upright and can never be inverted?" we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Pyramids**:
- There are three main types of ecological pyramids: Pyramid of Biomass, Pyramid of Numbers, and Pyramid of Energy. Each represents different aspects of an ecosystem.

2. **Define Upright and Inverted Pyramids**:
- An upright pyramid indicates a decrease in biomass, number, or energy as you move up the trophic levels.
- An inverted pyramid indicates an increase in biomass, number, or energy as you move up the trophic levels.

3. **Analyze Each Pyramid**:
- **Pyramid of Biomass**: This can be upright or inverted depending on the ecosystem. For example, in aquatic ecosystems, it can be inverted.
- **Pyramid of Numbers**: This can also be upright or inverted, depending on the number of organisms at different trophic levels.
- **Pyramid of Energy**: This pyramid is always upright. Energy decreases as it moves from one trophic level to the next due to energy loss (e.g., as heat).

4. **Conclusion**:
- Since the Pyramid of Energy is the only one that is always upright and cannot be inverted, the correct answer is the Pyramid of Energy.

### Final Answer:
The pyramid that is always upright and can never be inverted is the **Pyramid of Energy**.

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