The length of time required for half of the radioactive atoms in a sample to decay is its. a. half-life. b. relative date. c. radioactive date. d. period.

The length of time required for half of the radioactive atoms in a sample to decay is its half-life. The correct option among all the options that are given in the question is the first option or option "A". The other choices are incorrect and can be easily neglected. I hope that this is the answer that has come to your help.