Do jelly fish have eyes, and mouths? if so, why cant we see them?

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

as resources become scarce because of population growth, the growth decreases after few years due to lack of resources and food.