Fish fins are the most distinctive features of a fish, composed of bony spines protruding from the body with skin covering them and joining them together, either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. fish can have up to three dorsal fins. The dorsal fins serve to protect the fish against rolling, and assist it in sudden turns and stops. 1  In anglerfish, the anterior of the dorsal fin is modified into an illicium and esca, a biological equivalent to a fishing rod and lure.
emission of electromagnetic radiation during the course of chemical reactions. Such radiation, whether ultraviolet, visible, or infrared, is most commonly generated by oxidation. The radiation can usually be ascribed to the transfer of the oxidation energy to a molecule that is itself not undergoing oxidation.
A chemical reaction is a process that is usually characterized by a chemical change in which the starting materials (reactants) are different from the products. Chemical reactions tend to involve the motion of electrons, leading to the formation and breaking of chemical bonds. Direct Combination or Synthesis Reaction. 2  In a synthesis reaction two or more chemical species combine to form a more complex product. 3  A + B â AB. 4  The combination of iron and sulfur to form iron (II) sulfide is an example of a synthesis reaction :