Name of the five oceans in the world​

Historians are concerned with the accuracy of their writings and readings but are also aware of the inability of authors to know every angle of every story biases, perspectives, beliefs, and a variety of other differences history being told by one person at a time no one being totally accurate, as hard as we try really need on this, and you^^

Which item best completes the chart?

What is the main social system that existed in ancient china?