Which of the following best describes the difference between pre-steady state and steady state conditions?

• A. Pre-steady state is when the substrate concentration is constant, while steady state is when it changes.
• B. Pre-steady state is when the enzyme concentration is constant, while steady state is when it changes.
• C. Pre-steady state is when the product concentration is constant, while steady state is when it changes.
• D. Pre-steady state is when the enzyme-substrate complex concentration is changing, while steady state is when it remains constant.

Answer: (D)