Assertion : The plant biomass which serves as the food of herbivores and decomposers is said to result from the gross primary productivity. Reason : Gross primary productivity is the rate of net production of organic material (biomass).

Step-by-step solution

Net primary productivity is the available biomass for the consumption to heterotrophs (herbivores and decomposers). The rate of biomass production is called productivity. It has two aspects, gross primary productivity and net primary productivity. The rate of total production of organic matter during photosynthesis is known as gross primary productivity. Its considerable amount is utilised by plants in respiration. The organic matter synthesised by plants (GPP) minus the rate of respiration and other loss represent