In geophysics the refraction or reflection of seismic waves is used for research into the structure of the Earth's interior, and man-made vibrations are often generated to investigate shallow, subsurface structures.
Flatworms are considered acoelomate, since they have no body cavity, and roundworms are pseudocoelomate because they have a body cavity, but it is not derived from the splittiâ¦ng of the mesoderm tissue. Also, flatworms only have one opening in their digestive system unlike roundworms with two.
Platyhelminthes. Members of the phylum Platyhelminthes are flatworms, such as the planarian. Grubs and tapeworms are other examples of flatworms. Flatworms display bilateral symmetry; that is, the left and right halves of the body are mirror images of one another.Another characteristic of the platyhelminthes is cephalization.Cephalization means that one end of the animal functions as a head.latworms display bilateral symmetry; that is, the left and right halves of the body are mirror images of one another. Another characteristic of the platyhelminthes is cephalization.Cephalization means that one end of the animal functions as a head.