Concept:Ecological pyramids are graphical representations of trophic levels in an ecosystem.
Only three types are recognised in ecology: numbers, biomass, and energy.
Explanation:The pyramid of numbers shows the count of individual organisms at each trophic level.
The pyramid of biomass shows the total mass of living matter present at each trophic level.
The pyramid of energy shows the quantity of energy flowing through each trophic level.
These three are the standard ecological pyramids studied in biology.
There is no recognised ecological pyramid called the pyramid of organisms.
Therefore, the option that is not used in ecology is the pyramid of organisms.
Answer:Pyramid of organisms (Option D)