Why is the Ocean Salty?

What percentage of Earth's water is salt water?

• 95%

• 71%

• 3.5%

• 40%

How thick would the salt layer be if spread evenly over Earth's land surface?

• 150 meters

• 100 meters

• 200 meters

• 50 meters

Where does most of the salt in seawater come from?

• Soil and rocks on land

• Direct deposits from the atmosphere

• Artificial additions by humans

• Sea creatures

What role do hydrothermal vents play in the ocean's salinity?

• They remove salt from the water

• They support freshwater ecosystems

• They cool down the ocean water

• They add salt by reacting water with ocean floor minerals

What happens when underwater volcanoes erupt?

• They decrease the ocean's saltiness

• They increase the ocean's saltiness

• They create new marine life

• They form islands

What percentage of Earth's surface is covered by salt water?

• 71%

• 80%

• 50%

• 95%