Ecological pyramids are of
I. three types (age pyramids, energy pyramids and biomass pyramids).
II. four types (age pyramids, energy pyramids, number pyramids and biomass pyramids).
III. five types ((age pyramids, energy pyramids, number pyramids, tropical pyramids and biomass pyramids).
Select the statements with the correct option.

Options

A. I, Il and II
B. I and II
C. I only
D. None are correct

Answer

To solve the question regarding the types of ecological pyramids, we will analyze each statement provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Ecological Pyramids**:
- Ecological pyramids are graphical representations that show the relationship between different trophic levels in an ecosystem. They illustrate the distribution of biomass, energy, or numbers of organisms at each trophic level.

2. **Identifying Types of Ecological Pyramids**:
- The three main types of ecological pyramids are:
- **Pyramid of Numbers**: Represents the number of organisms at each trophic level.
- **Pyramid of Biomass**: Represents the total biomass (weight of living matter) at each trophic level.
- **Pyramid of Energy**: Represents the flow of energy through each trophic level, typically showing that energy decreases as it moves up the pyramid.

3. **Analyzing the Statements**:
- **Statement I**: Claims there are three types (age pyramids, energy pyramids, and biomass pyramids).
- This is incorrect because "age pyramids" is not one of the main types of ecological pyramids.
- **Statement II**: Claims there are four types (age pyramids, energy pyramids, number pyramids, and biomass pyramids).
- This is also incorrect for the same reason; "age pyramids" is not included.
- **Statement III**: Claims there are five types (age pyramids, energy pyramids, number pyramids, tropical pyramids, and biomass pyramids).
- This is incorrect as well, since it includes "age pyramids" and "tropical pyramids," which are not standard classifications of ecological pyramids.

4. **Conclusion**:
- Since all three statements are incorrect, the correct answer is that none of the statements accurately describe the types of ecological pyramids.

### Final Answer:
- The answer is **Option D**: None of these are correct.