U.S. Marine Corps Cpl. Ryan Nascimento, a chemical, biological, radiological and nuclear defense specialist, reads off casualty information for a nine-line medical evacuation request during a Combat Lifesaver Course practical application at Marine Corps Base Camp Pendleton, California, March 30, 2022. CLS is a three-day course that teaches Marines lifesaving medical techniques to eliminate preventable loss of life on the battlefield. - U.S. Marine Corps Cpl. Ryan Nascimento, a chemical, biological, radiological and nuclear defense specialist, reads off casualty information for a nine-line medical evacuation request during a Combat Lifesaver Course practical application at Marine Corps Base Camp Pendleton, California, March 30, 2022. CLS is a three-day course that teaches Marines lifesaving medical techniques to eliminate preventable loss of life on the battlefield.