Final answer:
The bolded text in the PSA aims "to establish credibility by presenting" medically supported facts and statistics from a reputable source, the U.S. Surgeon General, to highlight the dangers of smoking and encourage prevention.
Step-by-step explanation:
The author may include the information in the bolded text to establish credibility with the audience. By presenting alarming statistics and medically supported facts, Dr. Regina Benjamin, the U.S. Surgeon General, provides a powerful message about the harms of smoking. Citing the immediate and long-term health risks, such as lung disease, heart attacks, and premature death, the PSA encourages listeners to seek resources to help the next generation become tobacco-free. The connection to trusted health reports and the role the Surgeon General plays reinforce the validity of her statements and establish the author as a knowledgeable and authoritative source on the topic.