What's one benefit and one limitation of comparative investigations

I will go with the obvious answers, but  those are really impactful in some situations:

Benefit: You have much completer results, this is because you have, at least, two sets of data (that you know that are reliable because is most likely that you collected them)

This gives a wider range of application of the model or the results obtained of the investigation, and it allows to notice some anomalous behaviors in some cases (for example if you are studying how metal conducts electricity at different temperatures, you may found the point where it turns into a superconductor, and this gives a lot of information when investigating)

Limitation: You need to collect more than one set of data. This not only needs more time to acquire the data, but this also may need more equipment, more money, and more time to analyze the data.

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

your answer is, orbit around the nucleus