Ecological pyramids are of

Assertion : In a food chain, members of successive higher levels are fewer in number.
Reason : Number of organisms at any trophic level depends upon the availability of organisms which serve as food at the lower level.

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?

What does the given ecological pyramid represent?

Which of the following characteristics cannot be included in an ecological pyramid?

To show how many organisms are present at each level of a food chain,ecologists use a model called