Assuming nitrogen is an ideal gas, we use the relation PV=nRT tp predict what will happen to the system. From the equation, nR/P is constant. So, if the sample is cooled to 72K then volume would decrease. This decrease in volume would affect the density of the substance. It would increase its density. Therefore, the answer would be density.
It emphasizes the betrayal of the Japanese, as well as the severity and the number of the attacks.
