This is a research paper that explains the main reason for the terrorist attacks on 9/11.

A paper on the Great Depression drawing connections between the event and the rise of socialist policies in modern times.

So many outside factors can affect our emotions, such as movies, friends, books, television shows, something someone says, or even food. One of these factors is obviously music. Even without words, music can make us joyful or depressed, energized or sleepy.