what quote raises concerns about the sources usefulness as evidence that the fall of rome was inevitable

The correct question to this open question is the following.

Unfortunately, you did not include the options or quotes for this question, so we do not know the reference. However, we can help you with the following general comments.

The fall of Rome was inevitable when Barbarian tribes started to invade Rome- Indeed, they were the Germanic tribes like the Goths. It was King Alaric in 410, who captured the capital of the Western Roman Empire. Other factors impacted the fall of the empire, such as economic problems in Rome, overspending in the military, and the need for so many slaves. These factors combined with the fact that Emperor Constantine had decided to move the capital of the Empire to Constantinople, the most important city for the Byzantine Empire.

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.