One challenge faced by the european union is the?
a. inadequate educational and health care systems.
b. continued restrictions on movement between countries.
c. low standard of living compared to communist nations.
d. vast difference in per capita income among states.

vast difference in per capita income among states.

nuclear fission produces the atomic bomb, a weapon of mass destruction that uses power released by the splitting of atomic nuclei the fighting in iwo jima and okinawa affected the allies' pacific strategy because truman decided to drop the atomic bomb on mainland japan.

in 550 b.c.e. cyrus the great, the leader of the persians, conquered the medes and united the iranian people under one ruler for the first time. cyrus became the first king of the persian empire and went on to establish one of the largest empires in world.