What is a primary characteristic of magnetic north?

The primary characteristic of magnetic north is that it shifts position slightly over time. This is due to changes in the Earth's magnetic field caused by the movement of molten iron within the Earth's outer core, which can lead to variations in both the intensity and direction of the magnetic field. Consequently, the position of the magnetic north pole is not static; it gradually migrates, necessitating periodic updates to navigational data and tools that rely on magnetic compasses.

In contrast, magnetic north is not consistent and does change, which makes option A incorrect. Additionally, magnetic north does not always align with true north due to the magnetic declination, the angle difference between true north and magnetic north, which can vary based on geographical location. This means option C does not accurately reflect the nature of magnetic north. Lastly, while the Earth's rotation does have an effect on various aspects of our planet, the definition of magnetic north is primarily related to the magnetic field rather than rotation, making option D incorrect as well.