How did the constitution fix the problems of the articles of confederation? use at least one of the following principles in a paragraph response: rule of law, checks and balances, separation of powers, republicanism, democracy, or federalism.

The Articles of Confederation were established to govern the new country, with a weak executive power. It didn't take long before disputes between states and other matters caused them to rethink their plan and develop the US Constitution, with a more powerful executive branch (US President).
hope it helps

The transcontinental railroad provided a means of fast transportation. it cut a 6 month trip into 6 days, created jobs for many people and encouraged immigration. the homestead act played a huge role in western expansion; it allowed settlers to begin a fresh start, and gave them land in exchange for their residence for up to five years and a small fee.