What percentage of the Earth's surface is covered by oceans?

What is the deepest part of the ocean called?

Which ocean is home to the Great Barrier Reef?

What is the main cause of ocean tides?

Which ocean is the smallest?

Which famous lost city is believed to be under the ocean?

What type of water is found in estuaries where the ocean meets rivers?

Which sea creature produces pearls?

Which ocean zone receives no sunlight?

What is the largest animal in the ocean?