1. Economically, the world's transition from decentralization to integration is caused by division of labor, and economic globalization makes decentralized countries store each other.

2. The continuous updating of means of transportation (airplane, ocean transportation, etc.) and communication (telephone, telegraph and Internet) has promoted the process of economic integration.

3. With the economic integration, the political and cultural integration of various countries has been carried out step by step, such as Europe.

The world is getting smaller and smaller, cultural differences are getting smaller and smaller, and political differences are getting smaller and smaller.