It is the lithosphere that is broken into tectonic plates, which undergo some large-scale motions. The boundary regions between plates are aptly called “plate boundaries.” Based upon their motions concerning one another, these plate boundaries are of three kinds: divergent, convergent, and transform.
Tectonically stable means that this part of the continent has not moved for billions of years. The rock formation is important understanding the history of Earth since its unmoved and untouched state can provide ideas about how the Earth looked like as seen on the layers of the rock formation.
D. The Moon's rate of rotation is the same.
