Cnidarians such as jellyfish and corals have stinging cells called nematocysts. When touched they eject barbed threads tipped with poison.
How to Treat a Jellyfish Sting
How to Treat a Jellyfish Sting. Check out HowStuffWorks to learn more about jellyfish and how to treat a jellyfish sting. See more »
The Ultimate Coral Reef Quiz
The coral reef is an amazing, but threatened, ecosystem, with myriad marine life. Take this quiz to learn about preserving the world's coral reefs. See more »
The Ultimate Jellyfish Venom Quiz
The jellyfish is an unusual animal with a powerful venom. Take this quiz to learn more about the jellyfish's painful, venomous sting. See more »
Do jellyfish have the deadliest venom in the world?
Jellyfish venom is one of the deadliest toxins on Earth. Learn how humans and other animals trigger jellyfish venom and what the cure is. See more »
How Coral Reefs Work
Coral reefs are the rainforests of the sea, home to many, many marine fish species. Learn more coral reef facts and see coral reef photos and maps.
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How Jellyfish Work
Although jellyfish have been around for over 650 million years, they're stil very mysterious. Learn the basics and the jellyfish life cycle. See more »
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