Oceanography

The Great Barrier Reef is the world's largest coral reef system, located off the coast of Queensland in northeastern Australia. It stretches over 2,300 km and consists of nearly 3,000 individual reefs and hundreds of islands formed by living coral polyps.

The spring tide occurs when the moon, the sun and the earth make an angle of 180°

The standard average salinity of seawater is 35 parts per thousand (ppt), often expressed as 35/1 or 35‰. This means 35 grams of salt per kilogram of seawater. The other values (27, 80, 42) don't match the established scientific standard for ocean salinity.

Agulhas Current is the major warm current in the Indian Ocean.

Option (3) is the correct answer. 

Tides are the rise and fall of sea level caused by the combined effects of gravitational forces exerted by the moon, sun and rotation of Earth.

Ocean salinity is highest in sub-tropical regions (around 20°-30° latitude) due to high evaporation rates exceeding precipitation. The equatorial region has lower salinity due to high rainfall, polar regions have low salinity from ice melt, and tropical regions are too broad - the specific maximum is in sub-tropical zones.

The Dead Sea is the saltiest sea in the world with salinity around 34% (more than 9 times ocean salinity). The Red Sea is salty (4%) but not the saltiest. Arabian Sea and Caribbean Sea have normal ocean salinity (3.5%). The Dead Sea's extreme salinity comes from high evaporation in an endorheic basin.

The International Date Line approximately follows the 180° meridian and passes through the Bering Strait (between Alaska and Siberia). The Malacca Strait (between Malaysia and Sumatra) and Gibraltar Strait (between Europe and Africa) are nowhere near the Date Line. The Date Line was specifically placed in the sparsely populated Pacific Ocean region.

Kuroshio is a warm ocean current that flows in the western North Pacific Ocean, similar to the Gulf Stream in the Atlantic. The other options are all cold currents: Peruvian (Humboldt) flows up the west coast of South America, Labrador flows south along the coast of Newfoundland, and Canary flows along the northwest coast of Africa.

The time between two high tides averages 12 hours and 25 minutes, not exactly 12 hours. This is because the Moon takes approximately 24 hours and 50 minutes (not 24 hours) to return to the same position relative to Earth's surface, so the tidal cycle is half of that period. Option B would be the time between high and low tide, not between two high tides.

Correct Answer: Asia

If the Moon came closer to Earth, the gravitational pull on oceanic water would increase, causing higher tides. Tidal force is inversely proportional to the cube of distance, so a smaller distance means significantly stronger tidal effects. The temperature change (A), stopping of currents (B), and general sea level rise (C) are not direct consequences of the Moon's distance.

The Mariana Trench in the western Pacific Ocean is the deepest oceanic trench, reaching approximately 11,034 meters (36,201 feet) at its deepest point (Challenger Deep). The Tonga Trench, Japan Trench, and Kermadec Trench are all deep but none exceed the Mariana Trench.

Sea depth is traditionally measured in fathoms in maritime navigation. One fathom equals 6 feet (approximately 1.83 meters). While meters are also used in modern contexts, fathoms remain the standard nautical unit for depth measurement on navigational charts. Feet and nautical miles are used for distance, not depth.