Why use bronze as a symbol of civilization at that time?

1. Bronze at that time was a major feature, and its variety covered almost all aspects of society, so it represented the social outlook at that time.

2. The characters on bronzes are important historical materials at that time, which is of great significance to the study of today's society.

2. What is obviously different from the previous Stone Age and the later Iron Age is the casting of bronze, so this is the most distinctive feature of this era.