<span>a current study on the effects of stress on the body published by a medical journal
This would be the best source because it is the most current, least subjective, and most reliable. Since it is not personal experience or reaction, but based on medical tests, it would be the most accurate. Also, textbooks can be outdated so since this is current, it would add to the accuracy. </span>
Answer:
Tobacco use is the single most preventable cause of disease, disability, and death in the United States.
Where the comma should go in the sentence