Pyramid of number in a cropland ecosystem is

Inverted pyramid of biomass can be traced in one of the following ecosystems

The respiratory loss of producers, herbivores and carnivores are respectively

$A $ : Ecological pyramids cannot explain all the vital functions of any ecosystem.

$R$ : Pyramids actually does not explain the role of organisms working at more than one trophic levels.

Consider the following statements about ecological pyramids

$I.$ Charles Elton developed the concept of ecological pyramid

$II.$ After the name these pyramids are also called as Eltonian pyramids

$III.$ It is a graphical representation or pyramid shaped diagram which depicts the number of organisms, biomass and energy at each trophic level

Which of the statements given above are correct?

Write a short note on pyramid of numbers and pyramid of biomass.