In the context of homeostasis, what best describes a positive feedback mechanism?

• A. A process in which effectors act independently of sensors and control centers, producing random fluctuations around a set point
• B. A process in which the nervous system prevents any change in internal conditions by shutting down effectors
• C. A process in which a change in a variable triggers responses that counteract the change, returning the system toward a set point
• D. A process in which a change in a variable triggers responses that amplify the original change, driving the system further from its starting point until an endpoint is reached

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the concept of homeostasis, which is the maintenance of a stable internal environment within an organism despite external changes.
2. Step 2: Recognize that feedback mechanisms are processes that help maintain homeostasis by regulating physiological variables.
3. Step 3: Differentiate between negative and positive feedback mechanisms: negative feedback counteracts changes to return a system to its set point, while positive feedback amplifies changes, moving the system further from its starting point.
4. Step 4: Identify that a positive feedback mechanism involves a change in a variable triggering responses that increase or amplify that change, rather than reversing it.
5. Step 5: Conclude that the best description of a positive feedback mechanism is one where the response drives the system further from its original state until a specific endpoint is reached.