How many cultural layers are there in Yangshao Cultural Site?

Yangshao Cultural Site covers a total area of nearly 300,000 square meters, with a cultural layer thickness of about 2 meters and a maximum thickness of 4 meters. There are four cultural levels, namely, Yangshao middle culture, Yangshao late culture, Longshan early culture and Longshan middle culture. The most valuable thing in the site is a few tens of kilograms of millet 5,000 years ago, which shows that China has a long history of agricultural development.