Every five enslaved persons would count as three free persons.
Traditional economies don't use money or equivalent forms of currency: they're based on a more direct exchange of goods: people offer what they have and negotiate what they want to receive in return.
It is referred to as Bi-Laterael meaning two separate but equal parts
I believe the answer is theoretical model
A theoretical model is the foundation that could be held to support a certain theory for a certain research or study.
From the example above, the study is build on a foundation that both behavior and environmental factor could affect the subjects' overall health
