False.
Any time a scientific theory is challenged, it means it's not a good
theory. And this statement is not valid. In theoretical models, they are
revisited when there are further studies and discoveries found in a certain
area where they can be remodeled and reintegrated instead of disregarding its
credibility. Models, theories and paradigms are not challenged but rather
encouraged, they are supported in many studies since these theories and models
were created in order for us to understand a certain phenomenon but it would
likely help the scientific society to be updated in the new forms or spheres of
improvement rather than discouragement.
Such direct observational evidence is limited, however, and clouds remain the biggest source of uncertainty--apart from human choices to control greenhouse gases—in predicting how much the climate will change
