Final answer:
The island north of Australia has an antecedent boundary between Indonesia and Papua New Guinea.
Step-by-step explanation:
The island north of Australia with part of Indonesia on the Western side and Papua New Guinea on the east side has a fairly straight north-south border between them. This type of border is called an antecedent boundary.
An antecedent boundary is one that was established before the present-day cultural landscape developed. In this case, the boundary was likely determined by geographic features such as mountains or rivers, rather than being drawn based on the political or cultural divisions existing at the time.
In contrast, a geometric boundary refers to a boundary that is defined by straight lines or specific coordinates, while a natural boundary is determined by physical features like rivers, mountains, or coastlines.
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