What commodity from the north did traders bring across the sahara to the sahel?

gold
water
wood
salt

The creation of the trans-siberian railway allowed people to travel across russia. how could this railway impact russian culture?

Indicates how many people live in an area

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.