What varies by age and is measured in beats per minute?

The correct answer is related to pulse ranges, which indeed vary by age and are measured in beats per minute. Pulse rate, or heart rate, is a vital sign that indicates how many times the heart beats in one minute. This measurement is significant because it can fluctuate based on multiple factors, including a person's age, physical fitness, health status, and emotional state.

For example, newborns have a much higher pulse rate, averaging between 120 to 160 beats per minute, while the normal range for adults is typically between 60 to 100 beats per minute. As people age, their pulse rates can change due to variations in cardiovascular health and activity levels.

While respiratory rate, blood pressure, and body temperature are also vital signs that are affected by various factors including age, they do not possess the same direct correlation with age as pulse does. Respiratory rates can change with activity and health conditions rather than purely by age. Blood pressure tends to increase with age but is not measured in beats per minute. Body temperature remains relatively stable across various age groups, albeit there are slight variations in newborns and elderly individuals.