选出正确答案( )
A:Because they're kind.
B:Because they're cute.
C:Because they're ugly.
如图是某位同学设想的人造地球卫星轨道(卫星发动机关闭),其中不可能的是( )
设服从二项分布Bn,p的随机变量ζ的期望与方差分别是15和454,则n、p的值分别是( ).