Which form of government structure do states use?

a. federal

b. unitary

c. unilateral

d. command

I think the correct answer from the choices listed above is option A. The government structure that states use is the federal system. It is the government of the fifty states that constitutes the United States. It has three branches - legislative, executive, and judicial.

C. gemstones they are the only non metallic mineral from the list.