This website gives a really good explanation.
http://web.uvic.ca/~mbest1/engl366c2005/merchant1.html
Answer: People from Eastern Europe immigrated to the U.S. because...
Explanation: This would probably be the easiest way to restate the following question. It's simple and not confusing.
A search engine is a program that searches/identify items in a database which corresponds to keywords specified by the user. A meta search engine is an online information retrieval tool that uses data of a web (search English) and that makes its own results. A subject directory is a service which offers a collection of links to the internet which is posted by creators. Hope this helped!
