Final answer:
The statement that is not true about homeostasis is that it "shuts the body down in situations of extreme conditions." Negative feedback mechanisms are commonly used to maintain homeostasis, unlike positive feedback mechanisms, which are less common and usually amplify a response to complete a process.
Step-by-step explanation:
The statement about homeostasis that is NOT true is, "Shuts the body down in situations of extreme conditions." Homeostasis refers to the process by which living organisms maintain a stable internal environment despite changes in external conditions. The maintenance of body temperature is indeed an example of homeostasis, and it is primarily controlled by negative feedback mechanisms, which act to counteract changes that move the internal environment away from its set point. While some positive feedback mechanisms do exist, such as in childbirth and blood clotting, they are not designed to shut down the body but to amplify a response until a specific end goal is reached.
Negative feedback loops work to reduce the impact of a change and help return the body to a set value. For instance, if blood glucose levels rise after eating, insulin is released to lower it back to the normal range. In contrast, positive feedback loops, while less common, are designed to increase the deviation from the normal range until a process is completed. An example is the secretion of oxytocin during childbirth, which intensifies the contractions until delivery occurs.