Answer:
A law can no longer be in effect if Congress passes the law saying it has no effect.
It involved the re-appropriation of Indian land.
It was a chain reaction. Long story short, the countries were pulled into the war because of agreements they had with their allies. This treaty is what caused the countries to enter WWI, to protect and defend their allied countries who were already in the war.
They are taxes on goods that are imported into a country. A government may use the money from them to fund government operations.
