Final answer:
If body temperature was regulated by a positive feedback loop, the body would continue to increase in temperature rather than cooling down, which could be detrimental and lead to hyperthermia.
Step-by-step explanation:
Normally, body temperature is regulated by a negative feedback loop that acts to maintain homeostasis. In this system, a rise in body temperature triggers responses that promote heat loss, such as sweating and blood vessel dilation. When body temperature is regulated by a positive feedback loop instead, the physiological response would amplify the condition. This means that, if body temperature were to increase above normal levels, a positive feedback system would result in further increase in body temperature rather than bringing it down. In living organisms, positive feedback loops are not used for temperature regulation due to the destabilizing effect they have; they are reserved for processes with a clear endpoint such as childbirth or blood clotting.
In short, if a positive feedback loop were engaged in response to a rise in body temperature, the body would continue to get hotter, potentially causing hyperthermia, and would not work towards restoring the normal temperature range. This would be highly detrimental to the organism and is why temperature regulation in the body is assured by negative feedback mechanisms that act to negate the change and return the body to homeostasis.