Jellyfish are marine invertebrates belonging to the Scyphozoa class, and in turn the phylum Cnidaria.

The body of an adult jellyfish is composed of a bell-shaped, jellylike substance enclosing its internal structure, from which the creature's tentacles suspend.

Each tentacle is covered with stinging cells (cnidocytes) that can stun or kill other animals: most jellyfish use them to secure prey or as a defense mechanism.

Others, such as Rhizostomae, do not have tentacles at all.

For more information about the topic Jellyfish, read the full article at Wikipedia.org, or see the following related articles:

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Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

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