Practice question

Carbon-14 is formed in upper atmosphere by neutron interaction with nitrogen and incorporated through photosynthesis into living matter. Its half-life of approximately 5730 years is long enough that measurable amounts remain over millennia yet short enough to show measurable decay difference. Dead organisms stop carbon exchange, and remaining carbon-14 decays, enabling estimation of age up to 50000 years. Short-lived isotopes like phosphorus-32 survive days and sulfur-35 weeks, useless for archaeological timescales. Therefore 5730 year half-life uniquely identifies carbon-14 among common tracers.