Which among the following pyramid is always upright and can never be inverted?

Pyramid of energy

The correct answer is Option (2) - Pyramid of Energy

The Pyramid of Energy represents the flow of energy through different trophic levels in an ecosystem. It shows the amount of energy transferred from one trophic level to another and is always upright because energy is lost as heat at each trophic level. This means that the energy available decreases as you move up the food chain or trophic levels. Consequently, the energy pyramid cannot be inverted, as energy transfer is unidirectional, and the energy available at higher trophic levels is always less than that available at lower trophic levels.

On the other hand, the Pyramids of Biomass and Number can be inverted in some ecosystems depending on the specific structure of the ecosystem and the organisms involved.