The pyramid of biomass and the pyramid of number represent:

In a pyramid of biomass, $P$ is at the highest trophic level, $Q$ is at the second trophic level, and $R$ is at the lowest trophic level. Identify $P, Q,$ and $R$.

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

The pyramid of numbers becomes partly inverted and partly erect for which of the following?

In a tree ecosystem,the pyramid of number is

$A$: Ecological pyramid of biomass is generally inverted in the sea.
$R$: Biomass of fishes far exceeds that of phytoplanktons.