减数分裂过程中,染色体数目减半发生在( )
A:初级精母细胞形成时
B:次级精母细胞形成时
C:精子细胞形成时
D:精子形成时
My House
I am Jenny. Look! This is my house. What's in the house? Let me show you the rooms. This is the kitchen. Here is the bathroom. That is the living room. Here is my bedroom. That is Danny's bedroom. His bedroom is very nice.
每个人人格的基本标志是( )