F sharp.
F sharp is the leading note (7th degree) of the G major scale.
Technically speaking, D sharp major is: D#, E#, F* (F double Sharp,) G#, A#, B#, C* (C double sharp) D#. ***note: a double sharp (*) means that the note sounds a whole step above the principal note. For example: F*=G.
The mediant of any major scale is the note that is a third above the tonic (root) of the scale. In the key of F sharp major, the tonic is F sharp, so the mediant would be A sharp.
F sharp
The key signature that includes the note E sharp is the key of F sharp major.
The parallel minor of F-sharp major is F-sharp minor. A parallel minor key is the one with the same tonic note.
In B flat major the F is a natural F. In G major the F is F sharp unless you are told otherwise.
D major isn't actually a note. D major is a major scale based on the note D (D natural) and the scale has two sharps (F sharp and C sharp). There isn't anything special about D major since it requires both an F sharp and a C sharp, the most 'special' scale is C major since there are no flats or sharps needed.
An accidental can be a flat, natural, or sharp, used for a note NOT in the key (such as an F-sharp in C major).
An accidental can be a flat, natural, or sharp, used for a note NOT in the key (such as an F-sharp in C major).
What cancels an acciental in a Natural sign in front of a note. Example G Major (F#, F sharp). Any note in the line or space of the note F will be affected, but if there is a natural sign it will be restored to its original pitch.
G major, D major, E major, B major, F sharp major, F sharp minor, A sharp major, etc.