What country produce most of the oxygen of the world?

The majority of the world's oxygen is produced by the oceans, primarily through phytoplankton, which account for about 50-80% of global oxygen production. While no single country can be credited with producing most of the world's oxygen, regions with vast oceanic environments, like the Pacific and Atlantic Oceans, play a crucial role. Terrestrial plants, especially forests in countries like Brazil and Canada, also contribute significantly to oxygen production.