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.
Next. A. flatworms (Platyhelminthes) B. annelids C. chordates D. cnidarians Which of the following is found in vertebrates but not in invertebrates A. a dorsal nerve cord B. coelom C. three germ layers D. bilateral symmetry Symmetrical phyla include all of the following except A. chordates B. mollusks C....ext. A. flatworms (Platyhelminthes) B. annelids C. chordates D. cnidarians Which of the following is found in vertebrates but not in invertebrates A. a dorsal nerve cord B. coelom C. three germ layers D. bilateral symmetry Symmetrical phyla include all of the following except A. chordates B. mollusks C....