![](https://lstatic.shangxueba.com/sxbzda/h5/images/m_q_title.png)
According to the passage, the Earth' s magnetic field has______.A.misguided many a man and
According to the passage, the Earth' s magnetic field has______.
A.misguided many a man and animals
B.begun to Change to it's opposite direction
C.caused the changes on the polarities
D.been weakening it's strength for a long time
![](https://lstatic.shangxueba.com/sxbzda/h5/images/tips_org.png)