What is an essential factor for understanding changes in Earth's tectonic plates?

Understanding changes in Earth's tectonic plates primarily involves the concept of gravity. Gravity plays a crucial role in the movements of tectonic plates, as it influences the forces acting upon these plates, including the processes of subduction, continental drift, and mantle convection. The gravitational pull affects how the lithosphere (the rigid outer layer of the Earth) interacts with the underlying asthenosphere (a semi-fluid layer), leading to various tectonic activities such as earthquakes, volcanic eruptions, and the formation of mountains.

While magnetism, temperature variations, and wind patterns can have impacts on Earth's systems, they do not directly explain the movements and changes in tectonic plates as clearly as gravity does. For example, magnetism relates more to the Earth's magnetic field and geological features, while temperature variations can affect the physical states of materials in the Earth's crust but are part of a broader set of factors. Wind patterns primarily influence weather and climate and do not affect the tectonic processes themselves.