Answer:
b. they were ruled by emperors
The Aztec and Inca had a common structure in that they were both ruled by emperors.
Answer: Experimenter bias.
Explanation: Experimenter bias is the condition which describes a person as a part of experiment who is influencing the outcome of the experiment so that the desired or preferred results can be obtained.Experimenter bias is also known as research biasing.
The example mentioned in the question where Brian is conducting the study with sharing his views with the participants that he expects girls should perform better than boys in the experiment is example of experimenter bias.
The actual experiment should have been conducted without any thought sharing or acknowledgement which would have produced unbiased outcomes.But according to Brain's study, the expectations are conveyed ,therefore it will influence the result of the experiment as it becomes biased.
The source at the bottom would be information given by the people involved in a case.
The information given by the people that directly impacted by a certain case would most likely be designed to provide the most benefit for those people.
This is why united states operates on assumption that an accused would be innocent until he/she is proven guilty.
Information given by the people involved could only be held<em><u> as something to be confirmed </u></em>by other evidence or witnesses.