Nikkor G lenses have a built-in USM motor that permits auto-focusing on bodies with or without the focus motor. They also permit changing the aperture from the aperture dial on the body. Nikkor G lenses do not have an aperture dial on the lens itself.
Nikkor D lenses do not have a built-in USM motor. They can auto-focus from bodies equipped with a focus motor. Nikkor D lenses also have an aperture dial on the lens.
Do Nikkor D lenses permit aperture adjustments from the dial on the body, or does the existence of an aperture dial mean that one must use it? The G lenses presumably have some kind of motor, in addition to the focus motor, to change aperture. If adjusting the aperture of a D lens from the body is possible, does the aperture ring move? Probably not, since it would drain a lot of energy. If the aperture is controllable from the body, does this mean a D lens does have some kind of aperture motor after all?