What barrier is created by political boundaries that can restrict diffusion of ideas and goods?

• A. Borders and visa regimes; example: trade restrictions limiting cross-border diffusion
• B. Global internet access
• C. Meteorological features that limit travel
• D. Shared cultural festivals across borders

Answer: (B)

Diffusion is slowed when political boundaries impose controls on movement and exchange. Borders and visa regimes regulate who can cross, under what conditions, and for how long, while trade restrictions, tariffs, and quotas add costs and legal hurdles to exchanging goods and ideas. Together, these cross-border controls create a barrier that can segment diffusion, making ideas and products spread more slowly between countries or regions than within them. By contrast, global internet access tends to speed diffusion by linking people across boundaries; meteorological features are natural barriers, not political ones; and shared cultural festivals across borders often promote diffusion rather than restrict it.