Answer:
Radioactive half-life refers to the amount of time it takes for half of the parent isotopes in a radioactive substance to decay into their respective daughter isotopes. The parent isotope is the original, unstable radioactive isotope that undergoes radioactive decay, while the daughter isotope is the resulting isotope after the decay process. During each half-life, the amount of parent isotope decreases by half, while the amount of daughter isotope increases correspondingly. This process continues in subsequent half-lives until all of the parent isotopes have decayed into their daughter isotopes.