An empty office chair is at rest on a floor.
consider the following forces:
1. a downward force due to gravity;
2. an upward force exerted by the floor; and
3. a net downward force exerted by the air.
which force(s) act on the office chair?
1. none of the forces act on the chair since
it is at rest.
2. all three forces
3. 1 only
4. 1 and 2 only
5. 2 and 3 only
its is not 1 i am guessing 4

gravity

explanation:

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.