When the force of gravity pulling rocks toward the center of the earth matches the force of buoyant forces pus

Question

When the force of gravity pulling rocks toward the center of the earth matches the force of buoyant forces pushing back up on earth’s crust it reaches a state of

a. isostasy

b. tension

c. stress

Answer 1

isostasy

basically isostacy is the process where the earths crust acquires an equilibrium between the forces of gravity pulling on the crust and the forces of the action of the upper mantle (heavier material just beneath the crust) pushing back up -- it is similar to the action of water on the lighter ice floating on top of it