The biomass produced by plants in the oceans accounts for approximately how much of the total global primary productivity (in $\%$)?

State whether the following statements are True or False:
$I.$ The total organic matter synthesized by the producers in the process of photosynthesis per unit time and area is known as gross primary productivity.
$II.$ Net primary productivity is the weight of the organic matter stored by the producers in a unit area/volume per unit time.

In the equation $GPP - R = NPP$,what does $R$ represent?

Explain productivity and its types.

Which one of the following ecosystems has the highest annual net primary productivity?

Which of the following ecosystem types has the highest annual net primary productivity?