Which statement about the sahara is most closely
associated with the west african civilizations of
ghana and mali?
(1) irrigation systems made it possible to farm in
the sahara.
(2) salt mined in the sahara was exchanged for
gold.
(3) oases in the sahara served as their capital
cities.
(4) the sahara prevented the spread of islam to
the region.

How did the united states respond when north vietnam attacked a us warship and sent troops to south vietnam in the early 1960s? a.the united states declined to assist south vietnam against the north. b.us leaders authorized south vietnam to invade north vietnam. c.the president did not sign the gulf of tonkin resolution. d.congress authorized the president to escalate the conflict.