There paired fins can identify class Chrondrichthyes, which comprises namely of sharks and rays, their completely cartilaginous skeletons and biting jaws characteristic of the group. Chrondrichthyes are mainly carnivorous, and the sharks have highly adept senses for vision, olfaction, and hearing. They even posses a system of microscopic organs which can detect

changes in water pressure around the shall. Sharks do not possess gills flaps like a fish so a shark must continuously move in order to obtain enough oxygen to survey. The large teeth of a shark are evolutionarily derived from jagged skin scales. Which are apparent on shark's ancestor's Placodermi class. The digestion system of a shark contains a "spiral valve" intestinal system, which increases the surface area and lengthens the time food is digested in the unusually short intestine system of a shark. Sharks sexually reproduce. Unlike a shark, rays have flattened bodies so they can hide themselves in the sand at the bottom of any shallow water area and wait for a meal. Rays also have a whiplike tail for defense and jaws, which it uses to crush mollus

Some common words found in the essay are:
Sharks Rays, Osterrichhthyes Class, Fish Osterrichhthyes, Class Osterrichhthyes, Class Amphibian, Chondrichthyes Class, , fleshy finned, fleshy finned common, ray finned, sharks rays, bony fish, system shark, osterrichhthyes class, bony fishes, finned common,
Approximate Word count = 508
Approximate Pages = 2 (250 words per page double spaced)