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

In an ecological pyramid,the base always represents the $...A...$ and the apex represents $...B...$. Here,$A$ and $B$ represent:

What does the given ecological pyramid represent?

Which one of the following is not used for construction of ecological pyramids?

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

When a peacock eats snakes,which eat insects that thrive on green plants,the peacock is: