So right now, I will introduce you about my favorite animal, sea anemone. Sea anemone is an animal that live under water. Sea anemone is an animal, not a plant. many people confused sea anemone as plant, but actually sea anemone has:
Many sea anemones form symbiotic relationships with single-celled dinoflagellates, zooxanthellae or with green algae, zoochlorellae, that live within their cells.
A sea anemone is a sessile polyp attached at the bottom to the surface beneath it by an adhesive foot, called a basal disc, with a column-shaped body ending in an oral disc. Most are from 1.8 to 3 cm (0.71 to 1.18 in) in diameter, but anemones as small as 4 mm (0.16 in) or as large as nearly 2 m (6.6 ft) are known. They can have from a few tens to a few hundred tentacles.
A few species are pelagic and are not attached to the bottom; instead, they have a gas chamber within the pedal disc, allowing them to float upside down in the water.
The mouth, also the anus of the sea anemone, is in the middle of the oral disc surrounded by tentacles armed with many cnidocytes, cells that are both defensive and used to capture prey. Cnidocytes contain stinging nematocysts, capsule-like organelles capable of everting suddenly, giving the phylum Cnidaria its name. Each nematocyst contains a small venom vesicle filled with actinotoxins, an inner filament, and an external sensory hair. A touch to the hair mechanically triggers a cell explosion, which launches a harpoon-like structure that attaches to the organism that triggered it, and injects a dose of venom in the flesh of the aggressor or prey. This gives the anemone its characteristic sticky feeling. The sea anemone eats small fish and shrimp.
Unlike other cnidarians, anemones (and other anthozoans) entirely lack the free-swimming medusal stage of their lifecycle; the polyp produces eggs and sperm, and the fertilized egg develops into a planula that develops directly into another polyp.
Anemones tend to stay in the same spot until conditions become unsuitable (prolonged dryness, for example), or a predator attacks them. In that case, anemones can release themselves from the substrate and use flexing motions to swim to a new location. Most sea anemones attach temporarily to submerged objects; a few thrust themselves into the sand or live in burrows; a few are parasitic on other marine organisms, and some have symbiotic relationships with hermit crabs.
if you want to know more about sea anemone, just visit wikipedia.