I asked you if you had gone because it didn't seem like you knew how it worked. Not every college offers the same majors/minors/classes/etc. One college may specialize in medicine while another it may be agriculture, technology, or a million other things. There might be 500 colleges that offer a major in biology, but only a handful of those offer a concentration that you are interested in. It gets much more specific in graduate school. Certainly you must have realized these things, given your vast amount of knowledge gained through your prestigious academic endeavors.