What kind of animal is the ascaris?

Ascaris is a roundworm which is classified in the Phylum Nematoda, which is in the Animal Kingdom.

Features of Nematode worms include bodies which are not segmented and appear smooth on the outside. They are thin bodied worms. Some can be found in the soil living freely while others are parasitic and rely on a host organism as a way to obtain food.

They contain a body cavity or space between the inner cells (endoderm)...

Ascaris is a roundworm which is classified in the Phylum Nematoda, which is in the Animal Kingdom.

Features of Nematode worms include bodies which are not segmented and appear smooth on the outside. They are thin bodied worms. Some can be found in the soil living freely while others are parasitic and rely on a host organism as a way to obtain food.

They contain a body cavity or space between the inner cells (endoderm) and middle cells (mesoderm) however, this cavity is only partially lined with mesoderm and this cavity is not a true body cavity. It is referred to as a pseudocoelom.

They have two openings to their body consisting of an anterior mouth and a posterior anus.  

They don't have a true skeleton but fluid in their coelom and the muscles of the body wall help to support their body structure.

Diffusion is the method that gases enter and leave their body, and it provides the way for materials to slowly circulate throughout their body and for wastes to exit.

Ascarid worms are parasites that affect Humans and other animals. One example is the hookworm, which infect about one fourth of people on Earth. 

Someone needs to swallow fertile eggs that hatch into a larval stage in the small intestine where they can later be transported by the bloodstream to the lungs. 

The larvae complete their development and eventually can be coughed up and swallowed again. These will pass back to the intestine and develop into adults capable of producing more offspring. Thousands of eggs are produced by females daily which exit the host's body when they defecate. These can then be transmitted to other hosts.

A diagram has been provided to illustrate the life cycle of Ascaris lumbricoides.