A.Yawning results from fatigue or boredom.B.Other animal yawn for the same reason as humans.C.Animals yawn for a number of different reasons.D.Only social animals yawn.
A.Yawning results from fatigue or boredom.
B.Other animal yawn for the same reason as humans.
C.Animals yawn for a number of different reasons.
D.Only social animals yawn.