Which is the largest ocean on Earth?
AnswerThe Pacific
The Pacific is the largest and deepest ocean.
Nature · Facts & stats
Marine facts & stats
7 fact-checked facts about marine life, oceans and ocean science, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
About how much of Earth's surface is covered by ocean?
AnswerAbout 71%
Oceans cover roughly 71% of Earth's surface.
Going deeper
How many hearts does an octopus have?
AnswerThree
Octopuses have two gill hearts and one systemic heart.
What is the deepest known part of the ocean?
AnswerThe Challenger Deep in the Mariana Trench
The Challenger Deep is about 11 km deep.
What is bioluminescence?
AnswerLight produced by living organisms
Many sea creatures produce their own light chemically.
Expert level
Which tiny ocean organisms produce a large share of Earth's oxygen?
AnswerPhytoplankton
Phytoplankton photosynthesize and supply a large share of oxygen.
Which marine mammal uses rocks as tools to crack open shellfish?
AnswerSea otter
Sea otters use stones to open clams and urchins.
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