The population decreased because of diseases brought in by the white settlers that the Native Americans were not used to
In social studies, especially those in which you want to analyze or investigate the behavior, in many cases recreating the situation to be studied in a laboratory or the interaction of the researcher with the subject under investigation may be impossible or alter the result leading to false conclusions In these cases, the researcher resorts to naturalistic observation, which consists of observing or studying the subject in their natural conditions, in their environment, thus avoiding a change in the behavior of the researched, either because of the artificial nature of the experiment or because of the presence of a stranger, the researcher, in the environment.
Answer
In this case, the use of another method such as an interview or survey can result in a change of behavior or response by the interviewee, thus observing and recording the number of visitors without intervening with them is making a <em>naturalistic observation</em>
B) to spread slavery into new territories
