The pyramid of number is based on

In a pond ecosystem,the pyramid of numbers is ............ .

Which of the following statements is incorrect regarding the pyramid of energy, while three are correct?

Define ecological pyramids and describe with examples,pyramids of number and biomass.

$A$: 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.

Which ecosystem has the maximum number of producers per unit area?