A photosynthesizing plant does not strongly discriminate between the most abundant natural carbon isotope ( The discovery of natural carbon-14 by American chemist Willard Libby of the United States began with his recognition that a process that had produced radiocarbon in the laboratory was also going on in Earth’s upper atmosphere—namely, the bombardment of nitrogen by free neutrons.
In 1961 the isotope carbon-12 was selected to replace oxygen as the standard relative to which the atomic weights of all the other elements are measured.
Carbon-14, which is radioactive, is the isotope used in radiocarbon dating and radiolabeling.
..can, however, be traced with a Geiger counter or other detection device.
Different isotopes tend to concentrate in particular organs: for example, iodine-131 settles in the thyroid gland and can reveal a variety of defects in thyroid functioning.
Another isotope, carbon-14, is useful in studying abnormalities of metabolism that underlie diabetes, gout, anemia, and acromegaly.
Various scanning devices and techniques have been developed, including tomography...P) have been valuable in identifying the intermediate compounds formed during carbon assimilation.In this method, the activity of radioactive carbon ( carbon-14) present in bones, wood, or ash found in archaeological sites is measured.Because the rate at which this activity decreases in time is known, the approximate age of the material can be......these time clocks is controlled by the interaction of physical and biological processes, and so these influences must be disentangled before the clocks can be read.A notable example is the use of carbon-14 ( ..all the other elements combined.