All the adults were killed in the accident, but the two-year-old boy _______ alive.
A:ordered
B:expected
C:sprinkled
D:remained
如图,MN为⊙O的弦,∠M=50°,则∠MON等于____°.
下列基因型中最可能不是二倍体生物配子的是
1651年英国制定了《航海条例》,1849年英国宣布废除《航海条例》,这种政策上的变化原因是( )