Regular aerobic exercise gives an individual more endurance is a sentence that shows cause and effect. which word indicates the cause?
a. individual
b. exercise
c. endurance
d. regular

b. Exercise

If we conduct a research investigation in these given situation. More specifically, an experiment this would suggest a most probable scenario of a cause and effect situation or technically called causality. 

Here the Independent variable is the exercise 
The dependent variable is the endurance.

Hence regular EXERCISE increases endurance. 

Ithink due to shortage of water