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.
The Vietnam War was caused by many factors that contributed to the warfare in Vietnam during the years of 1959 to 1975. Most factors were the beliefs held by people who wanted to change or to prevent Vietnam becoming an Independent Country. Many people suffered due to these beliefs and policies and that the Vietnam War is now considered as one of the most distressing moments in the 20th Century.