Africa, the cradle of many old civilizations, is the second largest world continent, and the homeland of nearly one-eighth of the world population. Despite Africa's richness in natural resources, the average income per person, after excluding a few countries, is the lowest all over the world, and the percentage of inhabitants infected with contagious diseases is the highest. Development of Africa to help accommodate the ever-increasing population and secure a reasonable living standard to all inhabitants, though an enormous challenge is extremely necessary. Water is the artery of life,...