— Is it really a dog ?
—_____.
A:No, it wasn't
B:No, it isn't
C:Yes, he was
D:Yes, he is
如图表示在载玻片的两端各滴一滴含草履虫的培养液,然后把这两滴培养液连通起来,在右侧的培养液中加入一些食盐.请回答:
从脊髓发出的脊神经,主要分布在人体的( )。