Final answer:
The method used to date organic material less than 50,000 years old is radiocarbon dating, which relies on measuring the decay of the radioactive isotope carbon-14.
Step-by-step explanation:
The dating method used to date organic material that is less than 50,000 years old is radiocarbon dating, which uses the radioactive isotope carbon-14 (14C). In radiocarbon dating, scientists measure the amount of 14C remaining in a sample since the organism's death. Because 14C decays at a known rate, its concentration in the remains decreases over time. This decay allows researchers to calculate when the organism stopped ingesting 14C - which is at the point of its death - and thus determine its age within an approximate range.