ScienceAges 8+15 questions
Ocean Quiz
The ocean covers most of our planet and is home to the biggest animal that has ever lived, as well as some of the strangest. This quiz dives into the five oceans, the deepest trench, coral reefs, tides and the surprising facts behind octopuses, seahorses and starfish.
Read the questions and answers here, or host the quiz live: show it on a big screen, let players join on their phones with a PIN, and find out who really knows what lives beneath the waves.
The questions
1.Which is the largest ocean on Earth by area?
- APacific Ocean
- BAtlantic Ocean
- CIndian Ocean
- DArctic Ocean
Show the answer
Pacific Ocean. The Pacific is the largest and deepest ocean, covering about a third of Earth's surface.
2.Dolphins are mammals.
True or false?
Show the answer
True. Dolphins breathe air through a blowhole, are warm-blooded and feed their young on milk.
3.How many hearts does an octopus have?
- AOne
- BTwo
- CThree
- DEight
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Three. An octopus has one heart that pumps blood around its body and two that pump blood through its gills.
4.Which animal is the largest known to have ever lived?
- AWhale shark
- BBlue whale
- CMegalodon
- DGiant squid
Show the answer
Blue whale. Blue whales can grow to about 30 metres long and weigh well over 100 tonnes.
5.Off the coast of which country is the Great Barrier Reef?
- ABrazil
- BIndonesia
- CNew Zealand
- DAustralia
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Australia. The Great Barrier Reef lies off Queensland in north-east Australia and is the world's largest coral reef system.
6.Starfish are a type of fish.
True or false?
Show the answer
False. Starfish, also called sea stars, are echinoderms, related to sea urchins. They have no backbone, gills or fins.
7.Roughly how much of Earth's surface is covered by ocean?
- AAbout 71%
- BAbout 30%
- CAbout 50%
- DAbout 90%
Show the answer
About 71%. Around 71% of Earth's surface is ocean, which is why it is often called the blue planet.
8.What is the largest fish in the sea?
- AGreat white shark
- BBlue whale
- CWhale shark
- DManta ray
Show the answer
Whale shark. The whale shark is the biggest fish. The blue whale is larger, but it is a mammal, not a fish.
9.Which is the smallest of the five oceans?
- ASouthern Ocean
- BArctic Ocean
- CIndian Ocean
- DAtlantic Ocean
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Arctic Ocean. The Arctic Ocean, around the North Pole, is the smallest and shallowest of the five oceans.
10.In seahorses, it is the male that carries the eggs until they hatch.
True or false?
Show the answer
True. The female places her eggs in the male's pouch, and he carries them until the babies are born.
11.What is coral?
- AA plant
- BA rock
- CA type of seaweed
- DAn animal
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An animal. Corals are colonies of tiny animals called polyps. Many build hard skeletons that form reefs.
12.What do blue whales mainly eat?
- AKrill
- BSharks
- CSeaweed
- DSeals
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Krill. Blue whales filter huge amounts of krill, small shrimp-like animals, through plates called baleen.
13.What mainly causes the tides in the sea?
- AStrong winds
- BUnderwater volcanoes
- CThe pull of the Moon
- DRivers flowing in
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The pull of the Moon. The Moon's gravity pulls on the oceans, creating high and low tides. The Sun plays a smaller part.
14.The Challenger Deep, the deepest known point in the ocean, is in which trench?
- APuerto Rico Trench
- BMariana Trench
- CJava Trench
- DTonga Trench
Show the answer
Mariana Trench. The Challenger Deep lies in the Mariana Trench in the western Pacific, nearly 11 km below the surface.
15.Which gas, taken in from the air, is making the oceans more acidic?
- AOxygen
- BNitrogen
- CHelium
- DCarbon dioxide
Show the answer
Carbon dioxide. The oceans absorb carbon dioxide from the air. It forms carbonic acid in seawater, lowering its pH.
Play it live, everyone on their phones
Put the questions on a big screen, share the PIN, and the leaderboard keeps score. Change any question first — it becomes your own quiz.