Enzyme reaction rate depends on product formed per unit time

Steps:

• Define rate of reaction as mass of product divided by incubation time (µg/s).
• Calculate rate for tube A: 2.5 µg / 30 s = 0.083 µg/s.
• Calculate rate for tube B: 10.0 µg / 600 s = 0.017 µg/s.
• Calculate rate for tube C: 32.0 µg / 600 s = 0.053 µg/s; tube D same as B at 0.017 µg/s.
• Compare rates: A is highest.

Why A is correct:

• Rate = product mass / time per the definition of reaction rate in enzyme kinetics, yielding 0.083 µg/s for A.

Why the others are wrong:

• B: Lower rate (0.017 µg/s) due to less product relative to time.
• C: Moderate rate (0.053 µg/s), still below A's.
• D: Same low rate as B (0.017 µg/s).

Final answer: A