Each row is meant to convey its own concept. However, a concept may be represented by different words.
Sometimes you can combine two concepts into a single item. For example, your search may include the two concepts of College AND Student though depending on your results, you may wish to just search for "College student".
Join different concepts with AND. Join similar concepts with OR.
variables OR factors OR predictors OR influence OR relationship OR effects OR affect
Those these terms can be used in numerous contexts, at times they can be useful in constructing a search. These are in loosely related.