Jellyfish can survive in [[oxygen]]-poor water because they have a [[symbiosis | symbiotic]] relationship with [[algae]], which produce oxygen inside the jellyfish. <ref>http://www.microscopy-uk.org.uk/mag/artnov04macro/kfjellyfish.html</ref> | Jellyfish can survive in [[oxygen]]-poor water because they have a [[symbiosis | symbiotic]] relationship with [[algae]], which produce oxygen inside the jellyfish. <ref>http://www.microscopy-uk.org.uk/mag/artnov04macro/kfjellyfish.html</ref> |