Some cultures perceive ambiguity as an ongoing threat to be resisted whereas others perceive ambiguity as normal and non-threatening. This concept is known as:

Making the sleep-waking cycles shorter is not recommended because sleep

a. cycles cannot be altered by external factors. b. is an innate biological rhythm. c. is set by a number of unchanging external markers. d. must match a three to one ratio of time awake and time asleep.

Which nocturnal activity would increase the risk of dyssomnia?

a. eating a late heavy meal b. drinking water late at night c. taking a bath before bedtime d. Reading a book in bed