Answer: They all were agricultural hearths
they mostly had begun developing written language
cities began to form and from them empires often emerged
obviously they were centered around river valleys because of their naturally fertile soil
complicated political structures and governments often centered around a king began to form
Division of labor as a result of food surplus created by agriculture
Organized religious structures and beliefs began to form along with a priest class
Differences
different types of crops were common, like wheat in Mesopotamia and Nile, rice in Yang ze (yellow rice/ china)
some adopted Trade beyond local area such as Mesopotamia traded heavily with Indus, to the extent of my knowledge Yellow river did not yet
in Indid valley they were much more peaceful and their greatest structure was a massive bath house. They however were destroyed by the Aryans (not proto Nazis of course but the real aryans)
Some had more predictable flooding like the Indus Valley but the Nile and Mesopotamia were very unpredictable
Mesopatamia lacked the excessive resources beyond crops that many others had such as various types of ore