The Ultimate Factor Affecting Primary Productivity is ____

Question

The ultimate factor affecting primary productivity is ____.  
A) the organic matter in all the organisms of the ecosystem
B) the availability of water
C) the rate of photosynthesis
D) the availability of ATP
E) the amount of inorganic mineral ions in the soil

Accepted Answer

Primary productivity refers to the rate of production of organic matter by autotrophs through photosynthesis. Therefore, the rate of photosynthesis is the ultimate factor affecting primary productivity. Other factors such as availability of water, mineral ions, and ATP can also affect primary productivity, but they ultimately rely on the rate of photosynthesis. The organic matter in the organisms of the ecosystem is a result of primary productivity, not a factor affecting it.