65. The rate of an enzyme catalyzed reaction: 1. can be determined by measuring the increase in product concentration with respect to time. 2. is usually dependent on temperature and pH. 3. at saturating substrate concentrations, becomes zero-order with respect to substrate. 4. is independent of the enzyme concentration. (A) 1. (B) 1 and 3. (C) 2 and 4. (D) 1, 2 and 3. (E) All of them.