Final answer:
Ratings of Perceived Exertion (RPE) is an example of an exercise intensity factor, as it measures the intensity of exercise based on an individual's perception.
Step-by-step explanation:
Among the options provided, Ratings of Perceived Exertion (RPE) serves as an example of an exercise intensity factor. The RPE is a scale that measures the intensity of an individual's exercise based on their own perception of exertion.
This subjective measure can provide a more accurate assessment of exercise intensity than objective measures like heart rate, especially in cases where medication or other factors may affect physiological responses.