Answer:
Mainland region of southeast asia
Archipelago is known for extensive chain of islands
Explanation:
Mainland region of southeast asia
Mainland region comprises of countries like, Thailand, Laos, west Malaysia,Cambodia, Myanmar and Vietnam.
mainland region of southeast Asia is the region lies at eastern side of Indian subcontinent and north of this region is lies at south of china. This region is bounded by Indian ocean at west to pacific ocean in east.
Archipelago is known for extensive chain of islands
