Why was it very difficult to get lawas passed under the articles of confederation

Need on these last 2 questions on my social studies homework 5 and 6 then i’m done with the homework

By the end of the 1800s, there was a change in the nature of the immigrants coming to the united states. immigration from northern europe—england, ireland, germany, and scandinavia—declined, while immigration from italy, russia, and austria-hungary grew. in fact, between 1900 and 1910, more than three-fourths of all immigrants came from these three countries. unfortunately, these countries were far removed england, the home of our founders, and the immigrants who came from them had a hard time adjusting to life in their new country.

What from the columbian exchange had perhaps the biggest impact on the world?