Jellyfish including ancient living things too, because they were found 650 million years ago ... they can live in all types of sea water, even they also had been found in freshwater. Jellyfish do not have the respiratory system because their skin is thin and that their bodies already contain oxygen through diffusion. Jellyfish have no brain or central nervous system, but the jellyfish has a loose network of nerves, located at the epidermis, which is also referred to as "neural nets." Jellyfish consists of more than 90% water. Most of the masses is part of their umbrella jelly material called mesoglea, which is surrounded by two layers of cells that make up the umbrella (upper surface). While the bottom surface of the body known as the bell.
Jellyfish have a unique reproductive system, namely either-sex and male and female will release sperm and eggs into the surrounding water, where eggs are fertilized and grow into new organisms. Jellyfish have the deadliest poison and has caused at least 5568 deaths since 1954. Each tentacle has about 500 000 sindasites harpoon-shaped needle can inject into the victim.
Largest jellyfish species are a jellyfish to a lion's mane. This jellyfish is one of the longest known animals and that have the largest bell (body) with a diameter of 2.3 meters (7 feet 6 inches) and the tentacles reached 36.5 m (120 ft). These jellyfish ever found stranded on the Gulf coast of Massachusetts in 1870.
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