Which group of worms is the most progressive and more complex in evolutionary development.

Annular worms are a type of worms that are more complex, they are more developed than round and flat worms. Their body is divided by annular septa into segments. On each segment, there may be outgrowths on the sides-parapodia. The musculature consists of layers of longitudinal and annular muscles. They breathe with the help of the skin. A closed circulatory system and, most importantly, an anus has appeared in annelids.