physics (as an area of study)

contribution

contribute; make a contribution

largely; mostly

a lot / a majority

realm, territory, occupied area / field (area of expertise) / (mathematics) domain

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

physics, the physical aspects of a phenomenon or a system