Answer AND Explanation:
pH refers to the acidity or alkalinity of a substance. Most enzymes have an optimum pH close to 7 which is the intracellular pH. If the pH changes from the optimum for an enzyme, the rate of enzyme activity decreases. Extreme changes of pH denatures the enzyme.
When the substrate concentration is increased, the rate of an enzymatic reaction also increases up to a maximum level. Further increase in substrate concentration does not result in an increase in the rate of reaction because all the active sites of an enzyme are occupied.
