Ecological pyramids are of

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?

Which of the following organisms were not given any place in ecological pyramids?

If producer is a large tree that supports a number of herbivorous animals which are further attacked by ectoparasites, the pyramid of number shall be

Give scientific reasons : Energy pyramids are never inverted.