Pyramid of energy is

Inverted pyramid is found in

Pyramid of number in a cropland ecosystem is

Select the correct option w.r.t. Age pyramids.

Which kind of pyramid is represented by the given diagram

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?