Summary
According to the stimulus, sunlight contains both UV-A and UV-B radiation. UV-A causes wrinkles, and UV-B causes sunburn. Until about 10 years ago, sunscreen blocked UV-B, but did not block UV-A.
Strongly Supported Conclusions
These facts support the inference that before 10 years ago, sunscreen did protect against sunburn, but it did not protect against wrinkles.
A
Since about ten years ago, the percentage of people who wear sunscreen every time they spend time in the sun has increased.
This is not supported. The stimulus never mentions the percentage of people who wear sunscreen, so we can’t know if it has increased or not.
B
Most people whose skin is prematurely wrinkled have spent a large amount of time in the sun without wearing sunscreen.
This is not supported. The stimulus tells us that sun exposure is one cause of premature wrinkles, but we don’t know if it’s the predominant cause. Also, until at least 10 years ago, sunscreen didn’t even make a difference to wrinkling.
C
The specific cause of premature skin wrinkling was not known until about ten years ago.
This is not supported. Just because sunscreen didn’t protect against UV-A radiation until 10 years ago, that doesn’t mean the connection between UV-A and wrinkles was unknown. Maybe it just took a long time to develop effective UV-A blocking sunscreen.
D
People who wear sunscreen now are less likely to become sunburned than were people who spent the same amount of time in the sun wearing sunscreen ten years ago.
This is not supported. Based on the stimulus, sunscreen 10 years ago did protect against the UV-B rays that cause sunburn, so there’s no reason to believe that modern sunscreen provides more protection against sunburn.
E
Until about ten years ago, people who wore sunscreen were no less likely to have premature wrinkles than were people who spent the same amount of time in the sun without wearing sunscreen.
This is strongly supported. The stimulus says that before 10 years ago, sunscreen didn’t protect against UV-A rays, which cause wrinkles. That means that wearing sunscreen could not have lowered anyone’s chance of wrinkling prematurely.