Answer:The continental crust would depress the mantle less if it were thinner than its average thickness of 40 km. The thickness of the continental crust influences isostatic equilibrium, which is the balance of the weight of the crust and the buoyancy of the mantle beneath.
Thinner crust means less weight and thus less mantle depression, whereas thicker crust means more weight and thus more mantle depression. The depth of depression is also determined by the density of the crust and mantle. The greater the depression of the mantle, the denser the crust.
In general, tectonic processes and the formation and destruction of lithospheric plates determine the thickness of the continental crust. Thinner crust can be caused by processes like rifting or erosion, whereas thicker crust can be caused by processes like mountain formation or magmatic activity.