The diagram shows the layers of earth convection currents in which region influence the movement of tectonic plates

The answer is; Mantle

Convection currents in the mantle drive tectonic plate movements.  The convection currents in this regions are like those of water. The cooler upper mantles sink to the bottom and the hotter lower mantle rises. This circulation causes fiction drag with the overlying crust and therefore causes it to drift.    

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme