What did Roman engineers build to resolve the lack of water in cities? A:aqueducts
B:public baths
C:sewer systems
D:irrigation channels

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.

the answer is a) high entry costs