Only one, but the light bulb really has to want to change.
Four. One to change the bulb, three to stand around so he has someone to hi-five after.
3, a person, a ladder, and another lightbulb
Three, one to climb the ladder, one to shake it, and one to sue the ladder company.
None. Mice can't change light-bulbs as they are mere rodents without the physical or mental ability to do so. Not to mention it's much safer for them to pilfer food in the dark.
Squirrels they're the best at getting nuts out of their shells.
A psychiatric tryst.
