Which western industry's union efforts led to legislation mandating an eight-hour workday in Idaho, Arizona, and New Mexico by the early twentieth century?

mining

Explanation:

"a government in which power is divided between state and national levels". federalism is a system of government in which entities such and state and province, share power with the national government.

in 1989, tiananmen square in beijing was the site of china’s main industries. china’s government headquarters. -pro-democracy demonstrations. (second choice)