What role do natural resources play in the economy of a country?

Which describes the solid flying debris from a volcano

Humans have built artificial levees along the mississippi river to protect themselves and their property from floods. however, these structures also modify inland and coastal regions by disrupting the natural flow of sediment. artificial levees along the mississippi river a. reduce the amount of sediment deposited on floodplains and increase the amount of sediment deposited at the river's mouth. b. increase the amount of sediment deposited on floodplains and decrease the amount of sediment deposited at the river's mouth. c. increase the amount of sediment deposited on floodplains and at the river's mouth. d. decrease the amount of sediment deposited on floodplains and at the river's mouth.

The graph shows the number of employed workers in the united states in nonfarm jobs from 2008 to 2013. the best conclusion that can be drawn from the graph is that the number of nonfarm jobs remained consistent over time. started going down in 2008. went up every year since 2008. started going down in 2010.