What is a college student's declared main field of study called?

What is the name of a structure for venting smoke or gas from a fire? Paralyzed editor Jean-Dominique Bauby wrote a memoir by blinking one eyelid. Complete its title: "The ___ and the Butte… Isaac Newton graduated in 1665 without distinction from Trinity College at which university? Which word for a student comes from a Latin word that in Roman law meant an orphaned minor under a guardian? A 1978 study found people disliked which coin even before it was issued, because it looked too much like a quarter? A study running since 1958 on Michigan's Isle Royale examines the relationship between moose and which predator? A study reported in 2008 found that which siblings, long thought to share exactly the same DNA, actually have small gen… Which Italian stuffed pasta usually comes as square pockets filled with cheese or meat?