Question

Gross primary productivity is the rate of production of _________ during photosynthesis.
A. Organic matter
B. Oxygen
C. Carbon dioxide
D. Chlorophyll

Answer 1

Hint: Gross primary productivity (GPP) is associated with the rate of solar energy captured that can be used in the formation of carbohydrates or sugars. Photosynthesis starts with the capture of sunlight and the conversion of the energy to form complex substances which are used by different organisms.

Complete answer: In a food chain, some amount of energy is stored at a particular trophic level, which is known as primary productivity. Whereas, the energy that is stored at the consumer level is known as secondary productivity. It can also be stated as the new amount of organic matter produced at the consumer level. Consumers include herbivores, carnivores, and decomposers. The gross primary productivity is the amount of organic matter formed at a particular trophic level due to photosynthesis. Whereas, the rate of organic matter storage that is utilized by plants for the process of respiration is known as net primary productivity. It forms the total biomass available for different consumers.
Hence, the correct answer is option A.

Additional information: At each trophic level, only 10 percent of the energy is passed. The remaining 90 percent is dissipated in the form of heat.

Note: Solar energy is captured in carbohydrate molecules during the process of photosynthesis. Plants utilize this energy for the cellular metabolism processes. This energy can be used for the growth and development of plants. When the value for gross primary productivity is subtracted from the rate of energy loss to metabolism and maintenance, then the value for net primary productivity is obtained.