正常双亲产下一头矮生雄性牛犊。以下解释不合理的是()
A.该雄牛犊营养不良
B.B.雄牛犊携带了X染色体
C.发生了基因突变
D.双亲都是矮生基因的携带者
参考答案:B
根据句意填空,首字母已经给出。
1. When you want to post a letter,you need a s______.
2. You room is u______.You need to clear it up.
3. Edison was so c______that he invented a lot of things.
4. You have collected all different kind of dolls.We can say you have a big
c______
5. Many students have h______such as reading,painting and so on.
突起路标冲击试验时,实心钢球上方()处落下。
A、200mm
B、250mm
C、300mm
D、1000mm