Simplify the following text for a Grade 11 native English-speaking person.
Original: The entire reef system in the Florida Keys is encompassed by the Florida Keys National Marine Sanctuary , and significant portions of reef are protected as part of Biscayne National Park .
Simplified: The entire reef system in the Florida Keys is part of the Florida Keys National Marine Sanctuary , and large parts of reef are protected as part of Biscayne National Park .