How do I solve for this problem? What is the correct solution?

In which layer of earth do most earthauakes occur a_ inner core b_outer core c_mantle d_crust

You are making a solution of calcium chloride dissolved in water. you add solid, stir, and it dissolves. you add just a spatula tip full, stir, and the solid does not dissolve. how could you describe the solutions before and after adding the spatula tip amount

Choose all the answers that apply. as ocean depth increases, temperature decreases temperature increases pressure increases pressure decreases salinity increases density increases