What is a tectonic plate?

A tectonic plate refers to a large, rigid piece of the Earth's lithosphere that is constantly moving and interacting with other plates. This movement occurs due to the convection currents in the semi-fluid asthenosphere beneath the lithosphere. The interactions between these plates can lead to various geological phenomena, such as earthquakes, volcanic activity, and the formation of mountain ranges.

Understanding the dynamic nature of tectonic plates is key to grasping the processes that shape our planet. Unlike the other options that describe either non-moving components or structures that lack the significant interactions characteristic of tectonic plates, this correct answer emphasizes their mobility and the consequences of their interactions, which are crucial for understanding plate tectonics as a whole.