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

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?

The pyramid of energy in a forest ecosystem is

The pyramid that cannot be inverted in a stable ecosystem, is pyramid of

Pyramid of number in a cropland ecosystem is