Which ocean layer is described as "very light, sometimes wet, sometimes dry"?

• Shallow Seas

• Shore

• Open Ocean

• Deep Ocean

What temperature range do coral reefs develop in?

• 15-20 degrees

• 20-22 degrees

• 25-27 degrees

• 30-35 degrees

What is the main component of coral reefs?

• Silica

• Calcium carbonate

• Magnesium

• Sodium chloride

What percentage of the world's oxygen is provided by the ocean?

• 25%

• 50%

• 70%

• 90%

Which ocean layer is described as "very dark and very cold"?

• Shore

• Shallow Seas

• Sea Floor

• Open Ocean

What is the role of Zooxanthellae in coral reefs?

• They provide nutrients for fish stocks

• They create the color of corals

• They form the skeleton of corals

• They regulate ocean temperature

What happens to corals when they are killed?

• They turn black

• They become transparent

• They lose their color and the white skeleton is visible

• They dissolve completely

What is a major threat to the ocean mentioned in the document?

• Overfishing

• Deforestation

• Air pollution

• Climate change

What percentage of all known marine species live in coral reefs?

• 10%

• 25%

• 50%

• 75%

What is the estimated percentage of fish stocks that are fished over capacity?

• 10.4%

• 21.4%

• 31.4%

• 41.4%