1. Name, compare, and contrast Helmholtz's theory of color vision with Hering's theory of color vision. In your discussion, explain which theory best explains color blindness and afterimages. Finally, compare and contrast monochromats, dichromats and trichromats.
2. Identify the various stages of sleep and describe the physiological changes that accompany each stage. Also discuss the chronological sequencing and the timing of sleep stages throughout the night.