A U.S. Marine with Marine Aircraft Group 41, 4th Marine Aircraft Wing, searches for contaminated areas during a chemical, biological, radiological and nuclear individual survival skills course at Canadian Forces Base Cold Lake, Canada, June 14, 2019, in support of Sentinel Edge 19. CBRN training test Marines abilities to respond in the event of chemical, biological, radiological or nuclear contamination. Training exercises such as SE19 ensure Reserve Marines are proficient and capable of successful integration with active-duty Marines, making Marine Forces Reserve critical to the Marine Corps’ Total Force. (U.S. Marine Corps photo by Sgt. Andy O. Martinez)