Complex sentence: She works on several of the competing models of string theory in the quest to explain the fabric of the universe, and was the first tenured woman in the Princeton University physics department and the first tenured female theoretical physicist at MIT and Harvard University.
Split into simpler sentences: She works on several of the competing models of string theory in the quest to explain the fabric of the universe. She was the first tenured woman in the Princeton University physics department and the first tenured female theoretical physicist at MIT and Harvard University.