Correct: C. Arctic

The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It is located mostly in the Arctic north polar region and is almost completely surrounded by Eurasia and North America. Much of the ocean is covered by sea ice throughout the year, although this ice is rapidly melting due to climate change. It is also the least salty of all oceans because of low evaporation and the large amounts of fresh water coming from melting ice and rivers.

Correct: B. Atlantic

The Atlantic Ocean is generally considered the saltiest of the world's five major oceans. This high salinity is caused by several factors, including high rates of evaporation in its tropical regions and the lack of large rivers flowing into it compared to its size. The dense, salty water of the Atlantic helps drive the "Global Conveyor Belt," a system of ocean currents that regulates the Earth's climate.

Correct: B. Indian/Pacific

The Strait of Malacca is a narrow, 580-mile stretch of water between the Malay Peninsula and the Indonesian island of Sumatra, connecting the Indian Ocean to the Pacific Ocean. It is one of the most important shipping lanes in the world, serving as the main engine of trade between Europe, the Middle East, and East Asia. Approximately one-quarter of all the world's traded goods and oil pass through this strait every year.

Correct: C. 0.65

Approximately 65% of the world's fish species live in the ocean - marine fish species number approximately 18,000-20,000 while freshwater fish species total approximately 10,000-15,000. The total number of fish species is approximately 34,000.

Correct: C. Pacific Monsoon Gyre

The Pacific Monsoon Gyre or the North and South Equatorial Current systems are influenced by monsoonal winds - but the most specific monsoon-driven reversal occurs in the Indian Ocean, not the Pacific. The Kuroshio is a major Pacific western boundary current.

Correct: A. France

France has the world's largest Exclusive Economic Zone (EEZ) at approximately 11.7 million square kilometres - larger than any other country - because its overseas territories (French Polynesia, New Caledonia, Runion, Martinique, Guadeloupe, Mayotte, etc.) are scattered across multiple oceans.

Correct: A. Mediterranean Outflow

The Mediterranean Outflow (also called the Mediterranean Undercurrent) is a dense, salty water mass that flows out of the Mediterranean through the Strait of Gibraltar into the Atlantic - it spreads at intermediate depths (approximately 1,000 metres) as a recognisable salty intrusion.

Correct: C. Walker Circulation

The Walker Circulation is an atmospheric circulation system driven by the temperature difference between the warm western Pacific and cooler eastern Pacific - it drives trade winds that push warm surface water westward, causing upwelling of cold deep water in the eastern Pacific.

Correct: D. 0.9

Scientists estimate that approximately 91% of all marine species remain undescribed - there are currently approximately 250,000 known marine species but estimates suggest the true total may be 700,000-1,000,000 or more.

Correct: A. 1,335 million km

The world's oceans contain approximately 1.335 billion cubic kilometres of water - the Pacific alone contains approximately 710 million km (more than half the total), the Atlantic approximately 310 million km, the Indian approximately 264 million km, and the Arctic approximately 18 million km.

Correct: D. Antarctic Divergence

The Antarctic Divergence is an upwelling zone where surface water diverges around Antarctica - cold, nutrient-rich Circumpolar Deep Water rises to the surface here, creating the most productive waters in the Southern Ocean and supporting the Antarctic food web from krill to whales.