Pyramid of energy is :

Options

A. Always inverted
B. Always upright
C. Sometimes inverted sometimes upright
D. None of these

Answer

### Step-by-Step Solution:

1. **Understanding the Pyramid of Energy**: The pyramid of energy represents the flow of energy through different trophic levels in an ecosystem. It illustrates how energy is transferred from producers to various levels of consumers.

2. **Types of Pyramids**: There are two main shapes for pyramids in ecology: upright and inverted. An upright pyramid shows a decrease in energy, biomass, or number of organisms as you move up the trophic levels. An inverted pyramid indicates an increase in these factors as you move up.

3. **Energy Transfer**: According to the 10% law, when energy is transferred from one trophic level to the next, only about 10% of the energy is passed on. The remaining 90% is lost primarily as heat. This means that as you move from producers (1st trophic level) to herbivores (2nd trophic level) and then to carnivores (3rd and 4th trophic levels), the amount of energy available decreases.

4. **Conclusion on Shape of Pyramid of Energy**: Given that energy decreases as it moves up the trophic levels, the pyramid of energy is always upright. It cannot be inverted because energy does not increase at higher trophic levels.

5. **Final Answer**: The correct answer to the question "Pyramid of energy is:" is "always upright."