They are being treated as equal. In a setting that is unequal to the others.
I hope that helps
Answer:
Use words at a fifth grade level.
One log spanning 40 feet forms a natural bridge.
The phrase <em>spanning 40 feet </em>starts with a present participle <em>spanning, </em>and it is a phrase (given that there is no finite verb), which means that it is a participial phrase.