C) be sensitive to the ever-changing environment
D) avoid being swept away by rapid currents
15. By just the tip of the iceberg , Siegel suggests that ____________.
A) half-brain sleep has something to do with icy weather
B) the mystery of half-brain sleep is close to being solved
C) most birds living in cold regions tend to be half sleepers
D) half-brain sleep is a phenomenon that could exist among other species
Birds that are literally half-asleep-with one brain hemisphere alert and the other sleeping-control which side of the brain remains awake, according to a new study of sleeping ducks.
Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemispheres eye stays open and alert. Birds also can sleep with both hemispheres resting at once.
Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemispheres eye stays open and alert. Birds also can sleep with both hemispheres resting at once.
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