Final answer:
Positive feedback loops are typically necessary in biological systems for specific processes such as blood clotting and childbirth. They intensify a response until an endpoint is reached, ensuring the completion of important physiological events.
Step-by-step explanation:
Positive feedback loops are typically necessary in biological systems for specific processes such as blood clotting and childbirth. A positive feedback loop intensifies a response until an endpoint is reached, and in these cases, it helps to ensure the completion of important physiological events.
For example, during blood clotting, a cascade of chemical reactions is initiated by the release of clotting factors. Each activated clotting factor triggers the activation of the next factor, leading to the formation of a fibrin clot. The positive feedback loop in this process ensures the rapid and efficient formation of the clot, preventing excessive bleeding.
In the case of childbirth, the hormone oxytocin stimulates contractions of the uterus. These contractions cause the release of more oxytocin, leading to more intense contractions. This positive feedback loop continues until the baby is born.