With such huge increases in population, why has there been a direct equivalent increase in urban development (i.e., why is it such a small proportion of habitable land use?
A. People want to live close to where they work, which is usually the city or suburbs
B. There is not enough habitable land left for further urban development
C. Habitable land is already being used for livestock and crops
D. Many people can live in small people, such as high rises in cities