Answer:
1. First hand experience of poverty.
2. The United States was not invaded nor thoroughly destroyed.
3. Economic help.
Explanation:
1. Marshall came from a settler family in Virginia. His father suffered financial difficulties when George entered the Military Institute.
2. Marshall, who served in the first and in the second world war, had a more than average knowledge of the European continent. For him, having seen the destruction of Europe after world war II, he was aware that it might be difficult to explain the needs of millions of Europeans to Americans save at home in a country that didn´t suffer (civilians) like other countries did.
3. As my (grand)parents in the Netherlands once told me, the most difficult years of the world war came when it ended. There was nothing to eat.
The Netherlands, like most devastated European countries, urgently needed economically help in order to build up what was utterly destroyed.
Tip: look for the movie Europe by Lars von Trier.