151214-N-OF476-134 PACIFIC OCEAN (Dec. 14, 2015) Marines assigned to the 13th Marine Expeditionary Unit (13th MEU) board a Landing Craft Air Cushion (LCAC), assigned to Assault Craft Unit 5 (ACU) 5 in the well deck of amphibious assault ship USS Boxer (LHD 4) in preparation for an amphibious assault exercise. The Boxer Amphibious Ready Group (ARG) is underway off the coast of Southern California completing a certification exercise (CERTEX). CERTEX is the final evaluation of the 13th Marine Expeditionary Unit (13th MEU) and Boxer ARG prior to deployment and is intended to certify their readiness to conduct integrated missions across the full spectrum of military operations. (U. S. Navy photo by Mass Communication Specialist Seaman Eric C. Burgett/Released)