Fish are vertebrate animals, that is, they all have a vertebral column or âspineâ. There are two main groups of fish, bony fish (Teleosts) and cartilaginous fish (Elasmobranchs). As the common names imply, the skeletons of teleosts are made of bone while the elasmobranchs have cartilaginous skeletons.
Villard found a third type of radiation from pitchblende: gamma rays, which were much the same as X-rays. Then in 1896 Pierre and Marie Curie gave the name 'radioactivity' to this phenomenon, and in 1898 isolated polonium and radium from the pitchblende.
Dr. Glenn Seaborg and Edwin McMillan, Joseph Kennedy, and Arthur Wahl are credited with the discovery of plutionium. Plutonium was chemically identified in February in 1941 by Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy, and Arthur C. Wahl at the Berkeley Laboratory of the University of California (United States). They synthesized and isolated it in December of 1940 after bombarding uranium with deuterons.