posted by Kasey .
As a scientist, Carl is concerned with the intensity of lights in the modern human environment. 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 environment. Alertness, blood pressure, respiration rate, and muscle tension will be sampled in the morning and evening. Carl is studying:
1. light perception.
2. the relationship between mood and sleep.
I think it is a or d but I am pretty sure it is a.
What is "usual environment"? From your data, I don't see any of the choices as valid. However, if the measures are used as criteria for mood, I would pick 2.