Yes.
Nematodes have a pseudocoelom (a body cavity that is not completely lined by mesoderm), whereas flatworms have an acoelomate body plan (lack a body cavity). This means that nematodes have a body cavity, while flatworms do not have a true body cavity.
Acoelomate
A Planarian is an acoelomate, meaning they do not have a body cavity at all.
Acoelomate animals, like flatworms
Some of the general features of acoelomate animals include internal cavity for digestion, bilateral symmetrical, organ system organization and so on. These features are the ones that distinguish acoelomate animals.
A Cheetah has bilateral symmmetry and it is an acoelomate because they do not have a coelom
Flatworms, belonging to the phylum Platyhelminthes, do not have a pseudocoelom. They are acoelomate animals, meaning they lack a body cavity between the digestive tract and the outer body wall. Instead, their space between tissues is filled with a solid tissue called mesenchyme. This distinguishes them from organisms that do possess a pseudocoelom, such as nematodes.
yes
Acoelomate
Flatworms
Yes. Nematodes a multicellular.
They are not the same, except that they are both primitive vermiform clades which include many parasitic species.Nematodes are what is commonly called roundworms and are pseudocoelomates while flukes are acoelomate trematodes belonging to the platyhelminths.