Does anyone know my teacher means by this please help

Apopulation of black bears depends on salmon from a stream for food. if a drought causes the stream to run dry one year, how will this likely impact the black bear population?

The united states produces an average of 429 billion pounds of food annually. about 133 billion pounds of that food ends up as waste. the percentage of food that the united states wastes each year is %.

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!