Primary productivity is not limited by
a.
the availability of sunlight
b.
time
c.
the availability of nutrients
d.
access to water

B. Primary productivity, I think is the total energy fixated by photosynthesis. The only none limiting factor of photosynthesis there is time.

The answer is (d.) Access to Water.

In ecology, primary productivity is not limited by access to water.Primary production refers to the synthesis of the organic compound from the carbon dioxide either atmospheric or aqueous. It occurs through the process of photosynthesis which basically requires sunlight.

This is a time line from 685 to 978