The Concentration of the U

The concentration of the U.S. a.population into urban areas has had the following positive effect on our natural resources:

A) It has reduced the use of fossil fuels, as delivery of essential goods and services occurs in a more defined, smaller area.
B) It has helped protect the country's biodiversity by reducing the destruction and degradation of wildlife habitat.
C) It has reduced global warming, since the use of fossil fuels occurs only in very concentrated areas.
D) All of these answers.