2. What organelles are found in eukaryotic cells but not in prokaryotic cells? 3. In terms of physical features (e.g., size and shape), how do these two types of cells differ? 4. Are all prokaryotes unicellular or can they be multicellular? 5. Cite examples of organisms that are prokaryotes. 6. Aside from the species that you have examined, what are other examples of single-celled eukaryotic organisms?

Nematodes are commonly known as roundworms. They are free-living, very tiny organisms. They have an elongated and tubular body. These organisms have a nervous system and are mostly act as parasites to both animals and plants.

Platyhelminthes are also known as "flatworms" because as they are dorsoventrally flattened from head to tail. They are invertebrate, soft-bodied, acoelomate, unsegmented and have bilateral symmetry.