Simplify the following text for a Grade 9 native English-speaking person.
Original: Geographically , the Marianas are the northernmost islands of a larger island group called Micronesia , situated between 13 Â and 21 Â N latitude and 144 Â and 146 Â E longitude .
Simplified: The Marianas are the northernmost islands of a larger island group called Micronesia .