Answer:
1) GPP is the energy spent staying alive
Explanation:
Gross primary productivity is the energy that is spent by the organism to staying alive because energy is required by the organism for doing activities that is necessary for the survival. Gross primary productivity refers as the rate at which solar energy is captured in sugar molecules during the process of  photosynthesis. Producers such as plants use some of this energy for metabolism and cellular respiration as well as some for growth and building tissues.