Paleomagnetism can be used to estimate the age of the seafloor because the magnetic field of Earth in the geologic past is . a) unknown, but it is assumed to have been identical to today’s b) known to have been constant through geologic time, as seen by the remnant magnetization of iron-rich minerals in rocks c) known to have experienced numerous polarity reversals, as seen by the remnant magnetization of iron-rich minerals in rocks d) known to have been constant through time, on the basis of theoretical calculations

c) known to have experienced numerous polarity reversals, as seen by the remnant magnetization of iron-rich minerals in rocks.

Explanation:

Paleomagnetism is the study of the Earth's magnetic fields in sediment (rocks or other archaeological material). This can be used to estimate the age of sediment (or in this case, the seafloor) because it is known that the magnetic field of Earth experienced numerous polarity reversals. This allows is to employ such sequences as a chronologic tool. Paleomagnetism has also been a significant tool in the subjects of continental drift and plate tectonics.