If there are 10,000 calories of net primary productivity in an ecosystem, how much energy will be generally available to a primary consumer?

Trophic level—90% of energy consumed at trophic level is used by the consumer for survival and reproduction. The remaining 10% is transferred to the next trophic level. So the answer is 10,000 x 0.9 or 9,000 calories will  be generally available to primary consumer

An egg, or a sack of flour