Final answer:
Earth is home to five oceans: the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans, covering 71% of the planet's surface and playing crucial roles in the ecosystem.
Step-by-step explanation:
There are five oceans on Earth. The vast expanse of the planet's surface is about 71% covered by these global oceans. These bodies of water include the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern (or Antarctic) Ocean, and the Arctic Ocean.
Each ocean plays a vital role in the global ecosystem, with the Pacific Ocean being the largest and the Arctic Ocean being the smallest. Despite their size, oceans face significant challenges such as overfishing, pollution, and habitat destruction, which threaten marine biodiversity and the overall health of marine ecosystems.