In a grassland ecosystem, plants require about 10,500 J of energy to maintain their bodies and power the biochemical reactions needed for survival. In this ecosystem after one very rainy winter, you calculate that the plants added about 20,500 J of new biomass. What was the gross primary production (in J) in this ecosystem?
Group of answer choices
31,000
cannot be determined
10,000
100,000
310,000
