It helps more places get money
The main purpose of the Mounds was burial: the Mounds were a burial site for some distinguished people, such as kings. Other possible purpose was for ceremonies (ceremonies performed on top of the mound).
Answer: When the mind is unbiased
Explanation: Making rational decisions requires one to be unbiased either as a result of religious, racial or gender influence. It also requires one to be in the right frame of mind at the time of making the decision. Emotional decisions could occur if one's judgment is influenced by religious, cultural or social inclination or sympathy towards a particular group. It could also stem from one's present state of mind at the time the judgment is passed, hence making one's judgment more of emotional than rational.
In other to make rational decisions one should be in the right frame of mind, free from external influences which could induce bias into one's decision.