Chara (alga) Chara is a genus of charophyte green algae in the family Characeae. They are multicellular and superficially resemble land plants because of stem-like and leaf-like structures. They are found in fresh water, particularly in limestone areas throughout the northern temperate zone, where they grow submerged, attached to the muddy bottom.
The eustachian tube (also known as the auditory tube or the pharyngotympanic tube) joins the tympanic cavity with the nasal cavity (nasopharynx), allowing pressure to equalize between the middle ear and throat.
The middle ear couples sound from air to the fluid via the oval window, using the principle of mechanical advantage in the form of the hydraulic principle and the lever principle.