Which of the following statements regarding Earth's internal structure is/are correct? 1. The oceanic crust is heavier than the continental crust. 2. Most of the Earth's internal heat is contained within the mantle. 3. Large convective cells in the crust circulate heat and drive plate-tectonic processes. Select the answer using the code given below :

Statements 1 and 2 are correct. Oceanic crust (composed mainly of basalt, density ~3.0 g/cm³) is heavier and denser than continental crust (composed of granite, density ~2.7 g/cm³). Most of Earth's internal heat is indeed contained within the mantle, which makes up about 84% of Earth's volume. Statement 3 is incorrect because the large convective cells that drive plate tectonics occur in the mantle, not the crust. The crust is too thin and rigid for convection; mantle convection drives plate movements.