Radiometric dating radiometric dating allows us to determine an absolute, errorless date only works on rocks younger than 75,000 years relies on the fact that the daughter isotope decays to the parent isotope at a constant rate allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata

I think Radiometric dating relies on the fact that the daughter isotope decays to the parent isotope  at a constant rate. Radiometric dating is the process of determining the age of rocks from the decay of their radioactive elements. It is a techniques used to date materials such as rocks or carbon in which trace radioactive impurities are selectively incorporated when they are formed.