Final answer:
The training intensity of exercise that is likely to elicit the greatest percentage of improvement in VO2 max is 80-100% VO2 max. This range represents vigorous intensity exercise, which can enhance cardiovascular fitness and increase oxygen uptake.
Step-by-step explanation:
The training intensity of exercise that is likely to elicit the greatest percentage of improvement in VO2 max is b. 80-100% VO2 max. This range represents vigorous intensity exercise. According to the U.S. Department of Health and Human Services (HHS), vigorous activities are those during which a person could only say a few words without stopping to breathe.
Research has shown that when people exercise at 100 percent of the HHS guidelines, they can gain almost four years of life expectancy. Exercising at this high intensity helps to improve cardiovascular fitness, increase oxygen uptake, and enhance the efficiency of the body's energy production system.