How did steam locomotives lower the cost of transporting raw materials and finished goods?
a. they cost nothing to run because they ran on steam.
b. they could transport many materials or goods at once.
c. they were uncomplicated and inexpensive to build.
d. they were safe and cut the chance of costly accidents.

The persian wars started when emperor darius i began an invasion of greece. what caused darius to decide to attack greece? a. greek pirates had raided persia's merchant ships and coastal towns. b. greek armies had attacked and taken over land that belonged to persia. c. greek city-states had supported rebellions in the persian empire. d. greek leaders had declared independence from the persian empire.