Which of the following indicates a guest showing signs of life?

Respiration is a key indicator of a guest showing signs of life. Breathing is a fundamental physiological function that demonstrates the body's ability to take in oxygen and expel carbon dioxide, which is vital for sustaining life. A person who is breathing is generally exhibiting signs of life, indicating that their respiratory system is functioning.

High blood pressure alone does not necessarily indicate life signs, as it can be present in various medical conditions that do not reflect the overall life status of an individual. Persistent bleeding can be indicative of a severe medical issue, potentially leading to shock or even death, rather than demonstrating life. Cold extremities often suggest poor circulation or a drop in body temperature and can be associated with life-threatening conditions, which do not reflect a stable or thriving physiological state. Therefore, respiration clearly stands out as the most representative sign of life among the options provided.