Reactants bind to enzymes at the what?

Enzymes bring reactants together so they don't have to expend energy moving about until they collide at random. Enzymes bind both reactant molecules, called the substrate, tightly and specifically, at a site on the enzyme molecule called the active site

Explanation:

answer; i believe its echoic memory,it is believed to last three to four seconds; good luck

"d.) carbon dioxide and hydrogen sulfide"