Answer:
The lion's mane jellyfish's skin is so thin that the body receives oxygen through difussion.
Explanation:
The lion's mane jellyfish - giant jellyfish - is the largest species of jellyfish.
This species does not possess a 'usual' respiratory system that would enable to deliver oxygen to its cells. Instead, the lion's mane jellyfish's skin is so thin that the body receives oxygen through difussion.
Thanks to diffusion (oxygen molecules moving from an area of high concentration to an area of low concentration), oxygen that is already dissolved in the ocean then is converted into an equal amount of oxygen inside the jellyfish.