This island nation is the only one that shares a border with another country. new zealand australia french polynesia papua new guinea

Papua New Guinea

Explanation:

An island country is an independent country whose territory consists of an island or a group of islands. We can cite as an example of an island country the Papua New Guinea, which has the territory located to the north of Australia and has a unique terrestrial border: the Indonesia, to the west.

Some islands in Papua New Guinea are in serious danger of being submerged by rising sea levels caused by global warming. Example of this phenomenon was the removal of the population of the Carteret islands, which became uninhabitable and, in 15 years, must be totally submerged.

sure but add mine: melku504

explanation:

i'm in keystone 8th grade btw