The element is a clause if there is a subject and a verb, and it is a phrase if both of these parts of speech are not present. What comes after the introductory element is always an independent clause, or complete sentence, on its own, and the introductory element gives meaning to it.
A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. There are three main classes of parasites that can cause disease in humans: protozoa, helminths, and ectoparasites.
  Round worms are smaller (most are microscopic) worms and are usually parasites. One example of these is the hookworm. While most are parasitic, only a few will bother hu â¦ mans (most are parasitic only to plants). Segmented worms are the largest worms and are things like earthworms or leeches.They are the most complex worms and have developed digestive systems and a group of nerves that works like a brain. The main difference is that segmented worms are more complex organisms.8 people found this useful.egmented worms are the largest worms and are things like earthworms or leeches. They are the most complex worms and have developed digestive systems and a group of nerves that works like a brain.