How is the half-life of a radioactive isotope determined?
A. By measuring the time it takes for half the parent nuclei in a
sample to become daughter nuclei
B. By measuring the time it takes for half the daughter nuclei in a
sample to become parent nuclei
C. By measuring the time it takes for all the parent nuclei in a sample
to become daughter nuclei
D. By measuring the time it takes for all the daughter nuclei in a
sample to become parent nuclei
