The thermosphere is the hottest layer in the atmosphere because it is the closest to the sun air molecules generate heat greenhouse gases absorb cold the ozone layer reflects the suns heat

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

there’s no image attached but i can if you want: )