Answer:
B. Rapid development of technology.
Explanation:
Airplanes were not a thing yet. Railroads were still the main form of transportation at that time.
Physical factors that affect population density include water supply, climate, relief (shape of the land), vegetation, soils and availability of natural resources and energy. Human factors that affect population density include social, political and economic factors.
Answer:
C - Countries are increasingly independent for food supplies.
Explanation:
