Simplify the following text for a Grade 11 native English-speaking person.
Original: While the frill might have served to protect the vulnerable neck from predators , it may also have been used for display , thermoregulation , the attachment of large neck and chewing muscles or some combination of the above .
Simplified: The frill served mainly to protect the vulnerable neck from bipedal predators like Tyrannosaurus , who attacked from above .