Consider a sample of helium gas in a container fitted with a piston, as pictured below. The piston is frictionless, but has a mass of 10.0 kg. Which of the following processes will cause the piston to move away from the base and decrease the pressure of the gas? Assume ideal behavior. (3 pts) 10.0 kg base ↑ I. heating the helium II. removing some of the helium from the container III. turning the container on its side IV. decreasing the pressure outside the container