The following pyramid indicates:

The pyramid of numbers in a cropland ecosystem is:

Consider the following statements about ecological pyramids:
$I.$ Charles Elton developed the concept of ecological pyramid.
$II.$ After his 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?

When the number of organisms at successive levels are plotted,they assume the shape of a pyramid. This is called the pyramid of

The pyramid of number of a parasitic food chain in a tree ecosystem is

$A$: Pyramid of biomass is always upright for tree ecosystem.
$R$: Total biomass of a tree in a specific area is more than that of herbivores.