Name the structural features of the circulatory and nervous systems of annelid organs.

Ringed worms have a circulatory system. Flat and roundworms do not have this system. Consider earthworms, as they are the most common of all annelids on our planet. Their body is divided into segments – segments. Each segment has a blood ring. The circulatory system of annelids is of a closed type. Also, in each segment of the earthworm there is a nerve knot. In the front part of the worm, where the mouth opening is located, there is a large accumulation of neurons. They act as the brain.