The rate of formation of new organic matter by a rabbit in grassland is called –
A. Secondary productivity
B. Net primary productivity
C. Grass primary productivity
D. None of the above

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Hint: The productivity of producers is called primary productivity and that of consumers is called secondary productivity.

Complete answer: In an ecosystem, the producers are the ones which produce their own food. The producers are also the ones who produce food for the entire ecosystem. All the animals in the given ecosystem are dependent on the producers for their food requirements.
In ecology, the term productivity is used for the rate of generation of biomass in an ecosystem. It is usually expressed in units of mass per volume per unit of time. The mass can be of dry matter or the mass of generated carbon.
The productivity of autotrophs, like plants, is called primary productivity. The productivity of heterotrophs, such as animals, is called secondary productivity.
Primary productivity is the synthesis of new organic material from inorganic molecules such as water and carbon dioxide. It is brought about by the process of photosynthesis which uses sunlight to synthesize organic molecules such as sugars.
Secondary productivity is the generation of biomass in heterotrophic organisms in a system. It is driven by the transfer of organic material between trophic levels. It also represents the quantity of new tissue created through the use of assimilated food. Secondary productivity is sometimes defined to include the consumption of primary producers by herbivorous consumers only.
Organisms responsible for secondary productivity include animals, protists, fungi, and many bacteria.
Secondary productivity can be calculated through a number of different methods including increment summation, removal summation, the Allen curve method, etc. The choice between these methods depends on the assumptions of each and the ecosystem under study. For example, whether cohorts should be distinguished, whether linear mortality can be assumed, and whether population growth is exponential.

The answer to this question is option A.

Note: The biomass is the mass of living biological organisms in an ecosystem at a given time. The term biomass can also be used for species biomass, which is the mass of one or more species, or community biomass, which is the mass of all species in the given community. It can include microorganisms, plants, or animals. It can be expressed as the average mass per unit area, or as the total mass in the community.
Secondary productivity is the productivity of consumers. As a rabbit is a consumer, so productivity is called secondary productivity.