Which statement best defines positive feedback mechanisms?

• A. The response dampens the original stimulus to restore balance.
• B. An amplified response that accelerates the original change.
• C. A slow, constant adjustment toward a set point.
• D. A response that does not alter the original stimulus.

Answer: (B)

Positive feedback mechanisms push a process to continue and intensify the original change. The statement that describes an amplified response that accelerates the initial change captures this idea best. In positive feedback, the action makes things happen more quickly instead of returning them toward a baseline. Think of childbirth: as pressure from the fetus builds, contractions become stronger and more frequent until delivery occurs. Another classic example is the blood clotting cascade, where initial clotting activates more clotting factors to rapidly form a stable plug.

This contrasts with negative feedback, which works to dampen the initial change and bring the system back toward a set point, maintaining stability. A slow, constant adjustment toward a set point is characteristic of regulatory processes that correct deviations, not of a mechanism that amplifies the change. A response that does not alter the original stimulus would indicate no feedback effect at all.