Which of the following may limit primary productivity (photosynthesis)?
a. nitrogen
b. light
c. temperature
d. water availability
e. all of the above

e. All of the above

Explanation:

The primary productivity (photosynthesis) can be define as the total production of organic matter in the form of carbohydrates from available atmospheric carbon dioxide and water in the presence of sunlight, appropriate temperature, and nutrients by the plants or other autotrophs. The life on earth sustains due to primary productivity as the plants prepare their own food and these plants are consumed by the animals and other living beings.

On the basis of the above description, all of the above is the correct option. As plants or other autotrophs will not be able to synthesize their food in the absence of nitrogen (nutrient) obtain from the soil, light, temperature, and water.