Answer:
B
Explanation:
the second is the best explanation
<span>Refraction happens when there</span> is a bending of path of a light wave as it
passes across the boundary separating two media and the degree of bending is
determined in part by the total change in velocity as the light<span> passes from one medium to the other. In
addition, the change in speed experienced by a
wave when it changes medium can result in a number of beautiful optical effects. </span>
Different enzymes have specific active sites which can only catalyze one <span>substrate. Enzyme-substrate complexes are produced only when the substrate fits into the active site :)</span>