A:原子序数为118
B:相对原子质量为197.0
C:核电荷数为276
D:中子数为79
A.Here you are.
B.Yes, I want a bird.
C.That's right.
D.I'm six.
E.How nice!
(____)1.Two and three is five.
(____)2.This doll is for you.
(____)3.I want a pencil.
(____)4.How old are you?
(____)5.Please make a wish, Mike.
高等动物子代与亲代在染色体数目保持稳定,其原因是( )