Question

Which of these changes most likely results in an increase in the volume of a gas? Decreasing the pressure on the gas? Cooling the gas? Removing some of the gas form the sample?

Answer 1

Know the ideal gas law equation?

PV = nRT 

If you decrease P while keeping everything else constant, V increases. They are inversely related. 
P = 1/V
The first answer is correct.

Answer 2

Answer:

Decreasing the pressure on the gas.

Explanation: