Fill in the table “Comparative characteristics of flat, round and annelids”

Signs Flat worms Round worms Annelids
Symmetry type Bilateral Bilateral Bilateral
Number of body layers Double layer Double layer Three-layer
Features of the skin-muscle bag there is No there is
Body segmentation No No there is
The presence of a body cavity No Primary Secondary
The presence of the hindgut and anus No there is there is
Features of the excretory system Protonephridia Protonephridia Metonephridia
Features of the nervous system Nerve pillars Nerve pillars Periopharyngeal nerve ring and abdominal nerve cord

circulatory system

No No Yes, closed
Divided or hermaphrodite Hermaphrodites Dioecious Hermaphrodites
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