Why do historians have to include a citation when paraphrasing an idea from another source

In an economic downturn, what can happen in countries that depend on high taxes to fund social programs?

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.

When there are advances in technology, such as the personal computer, how might business productivity change? a) productivity is separate from technological advances so there is no impact. the new technology can replace outdated, less efficient, machinery. o) the businesses' products will no longer be demanded. d) manufactured items will be made elsewhere.