Water is supplied to the atmosphere by evaporation from the surface, and leaves the atmosphere via precipitation. the average amount of time a water molecule spends in the atmosphere can be derived by dividing the amount of water vapor in the atmosphere (1.1x1016 by the globally-averaged rate of precipitation to the earth’s surface of 3.1 mm −1 . using these data, calculate how many days, on average, a water molecule spend in the atmosphere before it precipitates out.