如图中，针对黄土高原水土流失采取的治理措施，错误的是（　　）

一个细菌菌落中的所有细菌都是同一个细菌的后代．（判断对错）

在下列实数$\frac{1}{4}$，$\sqrt{5}$，-$\sqrt{7}$，3.14，π．其中有理数出现的频率为（　　）

    This is a photo of Mr Black's family. The man with glasses（眼镜）is Mr Black, the father. The woman is the mother. They have a son and a daughter. The son is behind（在……后面）Mr Black. His name is Jack. He's 14. Kate is Jack's sister. She is 12. Jack and Kate are in the same school, but they are in different（不同的）grades. Jack is in Grade Three and Kate's in Grade One. They are good students.

一方水土养一方人，以下四个地方呈现“逐水草而居”的游牧生活的是 (      )