Grey matter refers to unmyelinated neurons and other cells of the central nervous system. It is present in the brain, brainstem and cerebellum, and present throughout the spinal cord.rey matter refers to unmyelinated neurons and other cells of the central nervous system. It is present in the brain, brainstem and cerebellum, and present throughout the spinal cord.
Kaz Tada (left) was one of those rounded up. Kaz was a Nisei  a person born in America of parents who immigrated from Japan. Nisei is a Japanese word meaning second generation. Isei refers to first generation immigrants, those who came the U.S. from Japan. And Sensei refers to third generation Japanese Americans.
Gosei is a supernatural guardian, who apparently was once mentored by Zordon and was tasked to be Earth's guardian. Awakened by the threat of the Warstar, Gosei recruits the Megaforce Power Rangers.