In a forest ecosystem, the pyramid of number is

Options

A. Upright
B. Inverted
C. Any of the two
D. None of the above

Explanation

### Step-by-Step Solution:

1. **Understanding the Pyramid of Numbers**: In an ecosystem, the pyramid of numbers represents the number of organisms at each trophic level. It helps in visualizing the relationship between different levels of the food chain.

2. **Identifying Trophic Levels in a Forest Ecosystem**:
- **Trophic Level 1 (Producers)**: The base of the pyramid consists of trees (producers) which are abundant in a forest ecosystem.
- **Trophic Level 2 (Primary Consumers)**: Many insects depend on these trees for food, representing the primary consumers.
- **Trophic Level 3 (Secondary Consumers)**: Small birds eat these insects, making them the secondary consumers.
- **Trophic Level 4 (Tertiary Consumers)**: Large birds that feed on small birds represent the tertiary consumers.

3. **Constructing the Pyramid**:
- At the base, we have a few trees.
- Above them, there are thousands of insects.
- Next, there are fewer small birds that consume the insects.
- Finally, the number of large birds is even less, as they are at the top of the food chain.

4. **Analyzing the Shape of the Pyramid**:
- The number of producers (trees) is much smaller than the number of primary consumers (insects).
- The number of primary consumers (insects) is greater than the number of secondary consumers (small birds).
- The number of secondary consumers (small birds) is greater than the number of tertiary consumers (large birds).
- This results in a spindle-shaped pyramid, where the base is broader and narrows towards the top.

5. **Conclusion**: In a forest ecosystem, the pyramid of numbers is spindle-shaped, which is not one of the standard options provided in the question.

### Final Answer:
The pyramid of number in a forest ecosystem is spindle-shaped.