不定项选择题 
Which of the following is not true according to the passage? ( )
A FNE shows that humans and animals have the same self - protection mechanisms when asleep.
B
The different external connections of the two hemispheres may cause one of them staying alert.
C
The reason why FNE causes alertness in the left hemisphere instead of the right hemisphere is not clear.
D
Physiological and environmental factors are probably the reasons to spur different alertness of the brain while asleep.
