Final answer:
Based on current and past growth rates of asthma prevalence, it is an educated guess that at least 25% of Americans will experience asthma symptoms during their lifetime, but without specific data on lifetime prevalence, this cannot be stated with certainty.
Step-by-step explanation:
You asked about the percentage of Americans that will experience the symptoms of asthma at some point in their lives. While there isn't explicit data indicating lifetime prevalence, we can draw insights from annual and current statistics to provide an estimate. Currently, approximately 8.2 percent of adults and 9.4 percent of children are affected by asthma in the United States. Given that asthma rates have been increasing, with a 157% growth from 2000 to 2010, it's likely that the lifetime prevalence is higher than these current figures.
If the annual rate of asthma is at 8.2 percent for adults and 9.4 percent for children, considering that multiple individuals might experience asthma at different times across their lifespan, and taking into account the substantial increase in asthma rates, some extrapolation could suggest that at least 25% of people may experience asthma symptoms during their lives, making option a) the closest choice given. However, without concrete data on the lifetime risk, this remains an educated guess rather than a definitive answer.