What single resistor could replace 20 Ω, 30 Ω and 50 Ω resistors which have been joined in series ?

co2reflects heat radiation back to earth buning coal and oil emits co2 globe warms

a displacement distance is size of displ

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.