Pyramid of numbers is

Options

A. always upright
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 is a graphical representation that shows the number of organisms at each trophic level in an ecosystem. It can help visualize the relationship between different levels of the food chain.

2. **Types of Pyramids**: There are two main types of pyramids of numbers:
- **Upright Pyramid**: This occurs when the number of organisms decreases as you move up the trophic levels. For example, in a typical food chain, there are many producers (plants), fewer primary consumers (herbivores), and even fewer secondary consumers (carnivores).
- **Inverted Pyramid**: This occurs when the number of organisms increases as you move up the trophic levels. This can happen in certain ecosystems, such as in a detritus food chain or a parasitic food chain, where a few organisms (like a single tree) support many consumers (like insects feeding on it).

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