The Marine Corps is only as capable as each and every Marine. To that end, Marines are assigned specific roles for which they are optimally trained. Each making a critical difference in a collective fight, Marines develop skills in specific Military Occupational Specialties (MOSs), and are expected to become experts in their respective fields. Together, Marines deliver the expertise our Nation demands in more than 300 disciplines, combining efforts to become a diversely talented, unwavering force.