Jellyfish are relatively low-level organisms, and their body structure is relatively simple. They also have eyes, but their eyes can not be regarded as real eyes, but a more primitive organ, called "dot eyes". Although this structure can also see certain objects, it is not particularly clear because there is no focal point for imaging. With this structure, jellyfish have a certain ability to sense light and shadow, and they can also sense when the light conditions change. Therefore, jellyfish can use this visual system to detect obstacles around them and avoid them.
The body shape of jellyfish is generally umbrella-shaped, with dots on the edge. There are many different kinds of them, and the number of dots of these different kinds is different. Some common jellyfish species usually have 8-10, not too many, and they are jellyfish with a less developed visual system. Some jellyfish have more eyes, and some even have more than 20 varieties. There is also a very special jellyfish, called "noctilucent jellyfish", which has more photosensitive organs distributed on their bodies, which also have the function of luminescence.
As mentioned above, jellyfish is a very simple body structure of organisms. They don't use lungs to breathe, they don't have lungs in their body structure. Not only that, but they don't have gills to breathe like fish, and in fact they don't have special breathing organs. But they also need to breathe, only with the help of their ectodermal cells. They need oxygen to breathe.
