Final answer:
Convection and convergence occur to form subduction zones and tectonic plates in Earth's crust.
Step-by-step explanation:
Convection and convergence are at work to form subduction zones and associated tectonic plates within the Earth's crust. Subduction zones occur mostly beneath the oceans and are regions where new crust is formed and old crust is destroyed as part of the cycle of plate tectonics. The process of convection drives the movement of the Earth's tectonic plates, causing subduction zones to form.