Their body cavity is called a pseudo coelom, they have a mouth and an anus.
They are not segmented nor do they have circulatory systems or respiratory systems.
They do have an excretory systems, waste comes out of the anus.
A roundworm has two nerve cords that transmit impulses in the roundworm.
They have a very simple nervous system.
Female roundworms can lay up to 200,000 eggs per day and there can only be up to 5,000 worms per host. The eggs from the female can be found in the human feces or contaminated waters. They can be hatched to the intestines to the blood and then carried to the respiratory system in the human body, which the small worms that are born will move to the throat, will then be swallowed back to the intestines which will make the host suffer so much sickness.
They have no skeleton just muscle.