Question

What occurs during one half-life?

Answer 1

On edgeunity it's option B, Half of a parent isotope undergoes radioactive decay to form a daughter isotope.

Answer 2

 Actually its the parent isotope that undergoes radioactive decay.

So option A and C is not correct.

And in one half life;

what happens is half of the parent isotope decays to form daughter isotopes.

Hence the correct option is B:

B. Half of a parent isotope undergoes radioactive decay to form a daughter isotope.