What units are used for gravitational potential energy? write the name, not the symbol.

Energy is Joules. It doesn't matter what kind of energy.

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

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.