What type of research involves observing ongoing behaviors to determine correlation?

The correct answer, observational research, is focused on the systematic observation of subjects in their natural environment without any intervention from the researcher. This type of research allows for the collection of data on ongoing behaviors, providing insights into patterns and relationships that may exist between different variables.

By observing subjects in real-time, researchers can gather information about how certain behaviors correlate with one another. For example, they may observe eating habits in conjunction with physical activity levels to identify trends or correlations.

On the other hand, experimental research involves manipulating one variable to see how it affects another, which is not the case in observational studies. Primary research refers to the collection of original data, which could be through various methods, including observational techniques, but isn't specifically tied to the act of observing behaviors solely. Secondary research involves analyzing data that has already been collected by others, which does not involve direct observation of behaviors. Thus, observational research is the most appropriate type for this question, as it directly pertains to observing behaviors to determine correlational relationships.