Radiocarbon dating also referred to as carbon dating or carbon-14 dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
The term for classifying and grouping organisms is Taxonomy. It is the science of defining and naming groups of biological organisms on the basis of shared characteristics.
Isotopes are variations of an element that have the same charge as the original element, but a different mass, which is caused by either more/less neutrons in the nucleus.