Question

what is Earth's uppermost mantle that overlaps with the crust; these are also the tectonic plates!

Answer 1

The Earth's uppermost mantle that overlaps with the crust and also consists of the tectonic plates is called the lithosphere. The lithosphere is a rigid and solid layer that includes the crust and the uppermost part of the mantle. It is broken into several large and small tectonic plates that float and move on the semi-fluid layer below, known as the asthenosphere. The movement of these tectonic plates is responsible for various geological phenomena such as earthquakes, volcanic activity, and the formation of mountain ranges.