Carbon is the element at the heart of all organic compounds, and it is such a versatile element because of its ability to form straight chains, branched chains, and rings. Because these chains and rings can have all sorts of different functional groups in all sorts of different ways (giving the compond all sorts of different physical and chemical properties), carbon's ability to form the backbone of these large structures is critial to the existence of most chemical compounds known to man. Above all, the organic molecules crucial to the biochemical systems that govern living organisms depend on carbon compounds.
The correct answer among the choices given is option B. Radioisotopes are isotopes that emit radiation because they have unstable nuclei. These are radioactive isotopes of an element. They are defined as atoms that contain an unstable combination of neutrons and protons.
The answer is option E. All of the above
