The madreporite of a starfish would be located on what surface?
The madreporite is located on the aboral surface of the sea star, which is the side opposite the mouth. Most people would consider this the "top" of the sea star.
Sea stars have two surfaces: the oral and the aboral. The oral is the side with the sea star's mouth and most people would think of it as the "bottom." The aboral is the opposite side, and this is where the madreporite lies.
The madreporite is the opening to the water vascular system. It takes in water that passes through the system and allows the sea star to move using its tube feet.
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