An example of inverted ecological pyramid is :

Pyramid of biomass of sea

The correct answer is Option (3) – Pyramid of biomass of sea

The pyramid of biomass in the sea is often inverted due to the higher biomass of fishes compared to phytoplankton. Phytoplankton, which are microscopic photosynthetic organisms, serve as the primary producers in marine ecosystems. They convert sunlight and nutrients into organic matter and form the base of the food chain.

The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton.The producers are smallest organisms while carnivores are large in size. Consequently , there is a gradual increase in biomass of organisms at successive trophic levels from producers onwards to top carnivores resulting in inverted pyramid. Thus, the biomass of phytoplanktons will be smaller than that of zooplanktons; the biomass of zooplanktons will be lesser than of primary carnivores ( e.g., small fishes).

Pyramid of number in a grassland and Pyramid of energy is a straight pyramid.