AP Human Geography

Answer - D - One improvement that can increase the sustainability of large urban areas with sprawling suburbs is the construction of integrated public transit systems like subway, bus, and rail.

Key Takeaway: Sustainable, or green, transport is an urban policy that replaces current urban and suburban transport systems with more fuel-efficient and environmentally-friendly alternatives. The term refers to any means of transport with a low impact on the environment, including human or animal-powered vehicles, low-carbon vehicles, or any kind of vehicle that can use renewable energy. Mandating vegetarianism, though likely an environmentally-conscious alternative, is unrealistic for large populations.