How do descriptive research questions differ from questions of relationship?

How do descriptive research questions differ from questions of relationship?

Tully (2014) outlined the types of research questions which include descriptive, relational, and causal (comparative). After reading their paper, write a three-page paper that addresses the following: How do descriptive research questions differ from questions of relationship? From questions of comparison? How should a researcher determine if prior research exists on the intended research topic? What factors should be used to gauge the quality of previous research? Why are these important in making this assessment? Should formulation of a research question precede or follow consultation with the scholarly literature? Please explain.