The active site, in biology, refers to the region of an enzyme where the molecules of substrate combine and goes through a chemical reaction. The active site comprises of the residues, which produce temporary bonds with the binding site (substrate) and residues that catalyze a reaction of that substrate, that is, the catalytic site.
Mountain lions/highest trophic levels receives less energy as energy is lost at each level/mountain lions are larger than most animals and require (smaller) individuals for food.