Respiratory system: they do not have lungs, therefore they breathe through their skin. Oxygen and carbon dioxide pass through the earthworm’s skin by diffusion.
Circulatory System: The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels. There are three main vessels that supply the blood to organs within the earthworm. These vessels are the aortic arches, dorsal blood vessels, and ventral blood vessels.
Digestive System: The digestive system is partitioned into many regions, each with a certain function. The digestive system consists of the pharynx, the esophagus, the crop, the intestine and the gizzard.
Hope this helped.