What is the difference between a direct democracy and a republic?

I suck at social studies

The graph shows a demand curve. which most likely accounts for the changes shown on the demand curve?

In which type of economy are these decisions made by the producers , consumers, and the goverment?

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.