The best answer to the problem is the bottom answer
Because the Greek city-states were weak and disorganized to unite after the Peloponnesian War.
Everything but attacks by Spanish soldiers and government roadblocks
If the house and the senate pass different versions of a piece of legislation, the differences will be resolved BY A CONFERENCE COMMITTEE.
Conference committee is the committee of the United State congress which is appointed by the house of representative and senate to resolve disagreement on a particular bill. The committee is usually made up of the senior members of both house of representative and senate who originally considered the legislation.
It made steel more cost effective
