Jellyfish don't have a respiratory system like humans or other animals with lungs or gills. They absorb oxygen directly through their skin!

Here's how it works:

* Diffusion: Jellyfish have a thin, permeable outer layer called an epidermis. Oxygen dissolved in the surrounding water can easily diffuse through this layer and into their cells.

* Simple Structure: Because they are so simple in structure, they don't need complex organs like lungs or gills to transport oxygen.

This method of oxygen absorption is common in small aquatic animals with high surface area to volume ratios.