Annelids are protostomial vermiform organisms measuring between 0.5 mm and 3 m long. They have a body of cylindrical section, with a symmetry bilateral and metamerized, that is to say, which seems composed of a series of identical rings.
Sometimes with teeth or chitinous jaws, the mouth is at the level of the prostomium, the first segment, while the anus is on the pygidium, the last segment. Between the two, the body contains a straight digestive tract and a closed circulatory system.
All of those systems are vital for a person to survive. If an organ stopped functioning it could cause you to die unless it is your liver and a few others.
