Please help me due in an hour

The sahel is located on the edge of the sahara desert. a.north b.west c.south d.east

List three reasons why explorers began to explore new, and old areas. [[ps: doesn't explicitly say where. i think it's more in general.

Between 1870 and 1916, approximately how many immigrants came to the united states? 10 million 25 million 75 million 125 million