Which is the largest and deepest ocean in the world?

The Pacific Ocean is the largest and deepest of the world's five oceans. It covers about 165 million square kilometres, which is about one-third of the Earth's total surface and more than all the land areas of the Earth put together. It stretches from the Arctic in the north to the Southern Ocean in the south, and lies between Asia and Australia on the west and the Americas on the east. It is roughly triangular in shape.

The Pacific Ocean was named by the Portuguese explorer Ferdinand Magellan in 1520. After a stormy passage through the strait at the southern tip of South America (now called the Strait of Magellan), he found the ocean calm and named it "Mar Pacifico", meaning "peaceful sea".

The deepest point on Earth, the Challenger Deep in the Mariana Trench, is in the western Pacific, near Guam. It is about 10,900-11,000 metres deep. If Mount Everest were placed there, its peak would still be more than 2 kilometres under water. The average depth of the Pacific is about 4,000 metres.

The Pacific is surrounded by a belt of active volcanoes and frequent earthquakes called the "Ring of Fire", caused by the movement of tectonic plates. About 75% of the world's active volcanoes and about 90% of earthquakes occur along this ring. The Pacific has the largest number of islands, about 25,000. It also contains deep ocean trenches, such as the Mariana, Tonga and Japan trenches.

The five oceans in order of size are: Pacific, Atlantic, Indian, Southern (Antarctic) and Arctic.

The Atlantic Ocean is the second largest and is shaped like the letter "S". The Indian Ocean is the third largest and the only ocean named after a country. The Arctic Ocean is the smallest and shallowest.

Why not the other options?

• ✗The Atlantic Ocean is the second largest and the busiest for trade.
• ✗The Indian Ocean is the third largest.
• ✗The Southern Ocean surrounds Antarctica and is the fourth largest.