1. Sensory adaptation refers to
A. a weakening of a neurotransmitter substance
B. a perceptual inversion principle
C. a decline in sensitivity after prolonged stimulation
D. an increase in sensitivity after prolonged stimulation
2. In order to maximize visual acuity at night, you should
A. look directly at the object you wish to see
B. turn your head at a slight angle to the object
C. close one eye
D. blink your eyes several times to hasten dark adaptation