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.
What were the causes of the Cold War? -Stalin didn't keep the agreements he had made with the Western Allies about holding free elections after the war in countries occupied by the Soviet Army. -The Americans didn't tell Stalin about the Manhattan Project, the building of the A- bomb. After using A-bombs successfully against Japan, USA refused to share the technology with USSR. -This scared the Russians, who thought USA may start a new war, against them, using A-bombs.