Answer:
The $20 billion can be used for tree plantation and crops growth.
Explanation:
Bill and Melinda Gates Foundation should use the $20 billion to grow trees. They should start tree plantation drive. This will improve the climate temperature and also the agricultural growth of the country will increase. The growth in crops will be sufficient for exports also. The GDP growth of the company will increase and the development of the country will also improve. The lifestyle of people living in the city will change to better and improvement will be witnessed in their health as they will consume fresh vegetables and fruits.