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
A proposed explanation for a wide range of observations and experimental results that is supported by a wide range of evidence. ... Most factors are held constant in a scientific experiment because you can only change one factor in an experiment so if you notice something, you'll know what caused it.
B. Formal operational stage of cognitive development
Like Geography, climate, times and environment system