What is the difference between gross primary production (GPP) and net primary production (NPP)?

a) NPP = GPP - plant respiration
b) GPP = NPP - plant respiration
c) Plant respiration = GPP + NPP
d) None of the above

a) NPP = GPP - plant respiration Explanation:Such type of total chemical production that takes place by the living organisms is known as gross primary production or GPP. The energy that is required to complete this process mainly comes from the sunlight that means solar energy and some times it is also obtained from the inorganic compounds in the case of lithotropic organisms. So the main production takes place by the process of photosynthesis and some amount is also produced by the chemosynthetic process.So the organisms that re responsible for the primary production are called primary producers such as plants, some bacteria. Living organisms utilize some formed organic compounds in the form of respiration and some other metabolic process. So the remaining or storage amount of the organic compounds that are formed by the organisms is called net primary production or NPP.So when the amount of respiration is subtracted from the amount of gross primary production then net primary production is obtained that is represented as NPP= GPP- plant respiration.