What distinguishes a dose-response curve from a plateau effect?

• A. Dose-response shows decreasing effect with dose
• B. Plateaus only occur at very low doses
• C. Dose-response is unrelated to dose
• D. Dose-response shows increasing effect; plateau indicates a point after which further dose yields no additional response

Answer: (D)

The main idea is that a dose-response curve shows how increasing dose tends to raise the effect, but only up to a maximum level. Once you reach that maximum, further increases in dose don’t produce more response—that point is the plateau. The statement that fits this distinction describes dose-response as increasing with dose and the plateau as the point after which additional dose yields no extra response.

The other ideas don’t fit: effects don’t typically decrease as dose rises on a standard dose-response curve; plateaus aren’t only at very low doses but occur when the system is saturated; and dose-response is directly related to dose, not unrelated.