The radiocarbon method was developed by a team of scientists led by the late Professor Willard F.
Libby of the University of Chicago after the end of World War 2.
Carbon-13 and carbon-14 are thus isotopes of carbon-12.
The relative dating method worked very well, but only in sites which were had a connection to the relative scale. When radiocarbon dating was developed, it revolutionised archaeology, because it enabled them to more confidently date the past, and to build a more accurate picture of the human past.
The archaeologist Colin Renfrew (1973) called it the development of this dating method 'the radiocarbon revolution' in describing its great impact upon the human sciences.
During the period of a plant's life, the plant is taking in carbon dioxide through photosynthesis, which is how the plant makes energy and grows.
Animals eat plants, and some eat other animals in the food chain.