Answer:
By adding radioactive monophosphates at different concentrations in order to measure the length of the poly-A tails and the degradation rate of target mRNAs.
Step-by-step explanation:
Polyadenylation is produced by adding multiple adenosine monophosphates to the end of the messenger RNA (mRNA) molecule. As a consequence of this, radioactive phosphates can be used as a label for poly (A) tails, thereby it is possible to measure the radioactive decay of target mRNAs over time.
The radioactive phosphorous tracers are produced by replacing these atoms in the phosphate group by radionuclides, thereby the radioactive decay is measured by tracing the radioisotopes of the target mRNAs.