Barrie Kreinik, an M.F.A. student in the Brown/Trinity program, is one of two actors starring in Trinity Repertory Company’s current production, The How and the Why, which runs through Dec. 30, 2012. Kreinik plays Rachel, a woman in her twenties who both bonds and spars with her mentor, Zelda, played by Anne Scurria, over the personal and professional consequences of their opposing views on the theory of evolution. Trinity describes the play as a “funny, gripping new play ... Fast and witty, inspiring and provocative, this wry gem from Sarah Treem (of HBO’s In Treatment) is both engrossing and powerful.”