Answer to Question 1A mass, such as the continental crust that floats on an underlying mass, should do so at an
equilibrium level, such that it extends at least as far beneath the upper level of the underlying material
as it does above the surface of that material
Answer to Question 2Continents grow by continental accretion. Eroded older continental crust, plutonic and volcanic rocks
from convergent plate boundaries and small terranes, fragments of seamounts, island arcs, and small
pieces of continents that were carried on oceanic plates collide with the continents and cause them to
grow.