In the geologic past,the polarity of Earth's magnetic field is ________.
A)unknown,but it is assumed to have been identical to today's
B)known to have stayed constant through geologic time,as shown by remnant magnetization of iron-rich minerals in rocks
C)known to have experienced numerous reversals,as shown by remnant magnetization of iron-rich minerals in rocks
D)known to have stayed constant through time,based on theoretical calculations

Question

Quizplus · Accepted Answer

The remnant magnetization of iron-rich minerals in rocks shows that the polarity of Earth's magnetic field has experienced numerous reversals in the geologic past. Therefore, choice C is the correct answer. Choices A, B, and D are incorrect because they do not accurately depict the known history of Earth's magnetic field.

In the Geologic Past,the Polarity of Earth's Magnetic Field Is