How is it that the open ocean produces the highest net primary productivity of Earthʹs ecosystems, yet net primary productivity per square meter is relatively low?

A) Oceans contain greater concentrations of nutrients compared to other ecosystems.
B) Oceans receive a greater amount of solar energy per unit area.
C) Oceans have the greatest total area.
D) Oceans possess greater species diversity.
E) Oceanic producers are generally much smaller than its consumers.