Pyramid of numbers is

Options

A. Always upight
B. Always inverted
C. Either upright or inverted
D. Neither upright nor inverted

Explanation

### Step-by-Step Solution:

1. **Understanding the Pyramid of Numbers**: The Pyramid of Numbers represents the number of individual organisms at each trophic level in an ecosystem. It can take different shapes depending on the ecosystem.

2. **Types of Ecosystems**:
- In terrestrial ecosystems, the Pyramid of Numbers is typically upright. This means that as you move up the trophic levels (from producers to primary consumers to secondary consumers), the number of organisms decreases.
- In some cases, particularly in aquatic ecosystems, the Pyramid of Numbers can be inverted. This occurs when a few large organisms (like fish) are supported by a large number of smaller organisms (like plankton).

3. **Analyzing the Options**:
- **Always upright**: This is incorrect because, as mentioned, the Pyramid of Numbers can be inverted in certain ecosystems.
- **Always inverted**: This is also incorrect since it can be upright in terrestrial ecosystems.
- **Either upright or inverted**: This option is correct because the Pyramid of Numbers can take both forms depending on the ecosystem.
- **Neither upright nor inverted**: This option is incorrect as the Pyramid of Numbers can indeed be either.

4. **Conclusion**: Based on the analysis, the correct answer is that the Pyramid of Numbers can be either upright or inverted. Therefore, the answer is option C.