If the LED has an output power of .001 Watts = .001 Joule/second, how many photons are output by the LED per second?

carla slowed down in the beginning of her trip, stopped, and then sped up

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.