Answer: Social Structure
Explanation: it has nothing to do with religion as everyone in Greece was Greek and only spartans lived like this (that I know of). Politics are not mentioned and this did nothing for the economy. Geography would have very little to do with this as there was nothing too out of the ordinary for that region. Achievements are both causes and effects of this, but mainly, this is something that determined how one was treated in Sparta. The strong were held in high regard.