Final answer:
New Zealand has the highest percentage of arable land among the mentioned nations, due to its fertile plains and favorable climate for agriculture.
Step-by-step explanation:
The nation with the highest percentage of arable land among the options provided is New Zealand. Arable land refers to the land suitable for agriculture and is a valuable resource for any country. In comparison with the other nations listed—Micronesia, Solomon Islands, Australia, and Papua New Guinea—New Zealand has more developed agricultural sectors and a temperate climate that supports a wide range of agricultural activities. While Australia has vast land, much of it is arid and not suitable for traditional farming practices.
Meanwhile, nations like Micronesia consist largely of small islands with limited arable land due to their topographies. The Pacific island nations often face challenges for farming due to forest cover, mountainous terrains, and in some cases, issues related to soil fertility. However, New Zealand's fertile plains, ample rainfall, and advanced agricultural practices give it a higher percentage of arable land, supporting diverse farming from dairy to horticulture.