  Recent observations have demonstrated that giant molecular clouds (GMCs) are
short-lived entities, surviving for the order of a dynamical time before
turning a few percent of their mass into stars and dispersing, leaving behind
an isolated young stellar population. The key question has been whether this
GMC dispersal actually marks a point of GMC destruction by stellar feedback
from the new-born stars, or if GMCs might be `immortal' and only dynamically
decouple from their nascent stars due to stellar drift. We address this
question in six nearby galaxies, by quantifying how the gas-star formation
relation depends on the spatial scale for scales between the GMC diameter and
the GMC separation length, i.e. the scales where an excess of GMCs would be
expected to be found in the stellar drift scenario. Our analysis reveals a
consistent dearth of GMCs near young stellar populations regardless of the
spatial scale, discounting the notion of `immortal' GMCs that decouple from
their nascent stars through stellar drift. Instead, our findings demonstrate
that stellar feedback destroys most GMCs at the end of their lifecycle.
Employing a variety of statistical techniques to test both hypotheses, we find
that the probability that stellar feedback concludes the GMC lifecycle is about
2,000 times higher than the probability that stellar drift separates GMCs and
young stellar regions. This observation strengthens the emerging picture that
galaxies consist of dynamic building blocks undergoing vigorous,
feedback-driven lifecycles that collectively regulate star formation and drive
the baryon cycle within galaxies.
