What specifically describes the balance between the lithrosphere floating atop the asthenosphere?
The balance between the lithosphere and asthenosphere is described by isostasy, which refers to the gravitational equilibrium between the Earth's crust (lithosphere) and the underlying mantle (asthenosphere). The lithosphere, being more rigid and less dense, floats on the semi-fluid asthenosphere, which allows it to adjust in response to changes in surface load, such as erosion or glaciation. This dynamic balance ensures that the lithosphere remains buoyant, maintaining stability in the Earth's topography over geological timescales.