Answer:
d. all of the above
Explanation:
a) Absolute dating technique is used to determine the age of rocks and fossil fuels, by the use of radioactive elements, such as, Carbon-14. The process involves the measurement of life of fossils through the remaining amount of radioactive element. It is possible by the knowledge of half life of radioactive element.
b) The radioactive isotope of Cobalt (Cobalt-60) is used to treat localized cancer. Other radioactive elements are also used to kill bacteria and treat cancer, such as, Iodine-131 is used to treat thyroid cancer
c) Radioactive elements are also used as tracers, such as Sodium-24, which is used as a tracer in blood. Other radioisotopes of Hydrogen, Carbon. Phosphorus and Sulfur, etc, are also used as tracers in different chemical reactions.
Thus, all the given options are correct and the correct option is all of the above (d).
