What Is the Productivity of an Ecosystem

Multiple Choice

What is the productivity of an ecosystem?

A) The rate at which the main primary producers of an ecosystem synthesise energy.
B) The rate at which primary consumers use energy.
C) The rate at which energy is synthesised by primary producers plus the rate at which it is recycled by degraders.
D) The total amount of material present at any time.
E) The difference between the energy produced by primary producers and that consumed by consumers.