Which flask would possess the lowest pressure if each of these flasks contains the same number of gas molecules?

The answer is 1. The first flask would possess the lowest pressure if each of these flasks contains the same number of gas molecules. As the temperature increases, the pressure of the flask also increases. Therefore as the pressure decreases the temperature also decreases so the flask with the lowest temperature would also have the lowest amount of pressure.

The increase in temperature means that the molecules speed up and hit the flask more often. This causes the pressure in the flask to become higher. The same can be said for molecules with a decrease in temperature. The molecules bump into each other and the sides of the flask less often.