Asteel cylinder with a moveable piston on top is filled with helium (he) gas. the force that the piston exerts on the gas is constant, but the volume inside the cylinder doubles, pushing the piston up.

which of the following answers correctly states the cause for the change described in the scenario?

the temperature increased.
the density of the helium atoms decreased.
the pressure decreased.
the helium atoms increased in size.

i don't know that i agree with that but what's the question ?

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.