U.S. Marine Corps Basic Reconnaissance Primer Course 9-18 students with Reconnaissance Training Company, Advanced Infantry Training Battalion, School of Infantry-West, supervise classmates who are conducting a bobbing exercise in which students exhale all the air in their lungs, sink to the bottom of the pool, and then return to the surface as a part of the Reconnaissance Aquatics Competency Test (RACT) at the Area 53 Pool at Marine Corps Base Camp Pendleton, California, Sept. 24, 2018. The RACT consisted of each student executing a series of aquatic exercises while having their feet tied together and keeping their hands behind their backs. The students conducted the RACT in preparation for follow-on training in the U.S. Marine Corps Combatant Diver Course where the same test is a requirement for course completion. (U.S. Marine Corps photo by Lance Cpl. Kerstin Roberts)