Final answer:
Papua New Guinea is the second-largest country in Oceania after Australia in terms of land area.
Step-by-step explanation:
After Australia, the second-largest country in Oceania in terms of land area is Papua New Guinea. Papua New Guinea is the largest country in the Pacific realm and is part of the region called Melanesia. It is known for its diverse physical terrain, including high mountains and unique human geography with multiple local groups and languages spoken.