Answer:
a) the balloons will shrink
b) temperature
c) volume of gas in the balloons
d) pressure and amount of the gas
e) The balloons can be set up and left at constant temperature. Possibly at room temperature to see if the same effect will be observed in it's volume.
Step-by-step explanation:
Charles law states that, the volume of a given mass of gas is directly proportional to it's temperature at constant pressure.
Hence, if we manipulate the temperature of a gas (e.g by immersing it into cold nitrogen) it's volume changes in response to temperature change at constant pressure.
A balloon at constant room temperature will not experience any decrease in volume as the balloon in our experiment does.