cover a many areas or topics, a lot of ground

a topic

diversity, variety

diverse

go across, go over / migrate

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

to research, to study

a piece of research, a study, investigation