The exact size, of course, depends on the playing time (in minutes and seconds), on how good the original compresses and the compression quality. 1 Mb a minute is a good approximation, in practice. I wouldn't trust 2 Gb to hold 1000 average downloaded songs. Just go for 4.
The causes of the Vietnam War were derived from the symptoms, components and consequences of the Cold War. The causes of the Vietnam War revolve around the simple belief held by America that communism was threatening to expand all over south-east Asia.
Basically, the Cold War was a rivalry between the United States as leader of the western democracies, and the Soviet Union and the nations that were controlled by the communists. Some causes of the Cold War included: Attempts by the Soviets and Chinese Communists to influence and take over areas in Asia and Europe.