ASa scientist, Carl is concerned with intensityof lights in the modern human evviroment. In his research project,Group A consists of volunteers who have agreed to sleep each night for a week with a 150 watt light bulb hanging over their bed. Group B will sleep in total darkness, and group C will sleep in their usual enviroment.Alertness, blood pressure, respiration rate, and muscle tension will sampled in the morning and evening. Carl is studying:
