the answer is true because do your own experiment..for example: if the inside of your home is warmer than the outside/ smoking a cigarette by an open window wen it's cold outside, you will notice the cigarette smoke comes back inside, that is because doing this creates the opposite wanted effect. the temperature difference from inside -outside causes the cold air to b drawn to the warmer air therefore creating this effect. similar to lower concentrations moving to higher concentrations with h2o..hope this helps, unless I misunderstood??