Complex sentence: True polar wander is a solid-body rotation of a planet or moon with respect to its spin axis, causing the geographic locations of the North and South Poles to change, or "wander".
Split into simpler sentences: True polar wander is a phenomenon in which a planet or moon undergoes a solid-body rotation with respect to its spin axis. As this occurs, the geographic locations of the North and South Poles change, or "wander".