Pyramid B (Spindle Shaped): This represents a single large tree supporting many herbivorous birds, which are then eaten by a fewer number of carnivorous birds (top predators). In a single tree ecosystem, the base is small because there is only one (or few) producer. Pyramid A (Inverted): This typically represents a pyramid of biomass in an aquatic (ocean/pond) ecosystem, where the biomass of phytoplanktons is much less than the biomass of the fishes that eat them.

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