Cardiorespiratory fitness, measured as VO2 max in mL/kg/min (maximum oxygen consumption), is associated with increased longevity. Recent evidence suggests that higher fitness increases the life span. Those with a low VO2 max have a life expectancy after 60 years of 7 years, those with moderate VO2 max of 15 years, and those with a high VO2 max have a life expectancy after 60 of 23 years. Which of the causal criteria is illustrated with this example? a. Temporal relationship
b. Dose-response effect
c. Replicability of findings
d. Specificity of association
e. Strength of association