The pyramid of biomass shows a sharp _________________ at higher trophic levels.

In most ecosystems, all the pyramids, of number, of energy and biomass are upright, i.e., producers are more in number and biomass than the herbivores, and herbivores are more in number and biomass than the carnivores. Also energy at a lower trophic level is always more than at a higher level.
In an upright pyramid of biomass in a grassland ecosystem, the pyramid shows a sharp decrease in biomass at higher trophic levels.