The column of mercury in the barometer is lowest when the barometer is ion location 4. Atmospheric pressure measured by the barometer decreases with an increase in altitude. Atmospheric pressure is caused by the column of air above the ground level at any given point on the earths surface thus an increase in altitude leads to a decrease in this column leading to a decrease in atmospheric pressure.
Non polar has a symmetry. Polar has no symmetry. You can tell from shape.
