Simplify the following text for a Grade 7 native English-speaking person.
Original: The water hemisphere has only one-eighth of the world 's land , including Australia , New Zealand , Antarctica , the Malay Archipelago , and the southern part of South America .
Simplified: The water hemisphere has only one-eighth of the world 's land , . Australia , New Zealand , Antarctica , a small part of Southeast Asia and the southern part of South America are in the water hemisphere .