Robin asks Nataki why the work done on the gas that is compressed quasi$-$statically increases as the piston is depressed. Which of Nataki's responses are correct? $($Select all that apply.$)"$ W $=$ Fd cos $,$ and because the force on the piston and displacement are in the same direction, $=0,$ and the work done on the gas is positive." "Work is the transfer of energy from one physical system to another, and when the piston is depressed, the energy of the moving piston is transferred to the gas in the form of work." "When the gas is compressed, its volume decreases, resulting in work done on the environment, which is positive." "The external force acting on the piston is in the opposite direction from the displacement vector, and because W $=$ Fd sin $,$ the resulting work on the gas is positive."