Read this conclusion from "Heads Up on Sports Safety."

Do the precautions of these helmets mean that football is safe? Football and other sports are safer; however, even with the best helmet, head trauma is still possible, especially after the head has been hit repeatedly. More information is still surfacing about the long-term possible effects of head injury to professional athletes.

Now read the supporting text appearing next to a photo of a 1904 football game in the article.

1904 football game between the University of Chicago and the University of Michigan. That year there were 18 football deaths and 159 serious injuries, due to lack of proper helmets, safety equipment, and loose rules. President Theodore Roosevelt urged the colleges to make the game safer. However, in 1905, there were still 19 player deaths and 137 serious injuries.

How does the supporting text of the 1904 football game relate to the purpose of the main text?

It shows how sports safety has not changed over time.
It describes how football games are played.
It provides an example of danger in sports in the past.
It illustrates the popularity of team sports in America.