aka the "C" clef ... the middle line is the note "C".
The base clef is also called the f clef, because if you look at it, the line in between the two dots of the base clef when it is on a staff is the f line.
The Great Stave is the combination of both the treble clef and the base clef
The 'Cello is in Concert Pitch (C) so A above middle C will equal 440 (same as the piano)
bass clef
violas dont use treble clef they use alto clef
Bass and also tenor clef.
If you mean which clef does a violinist use then it's the treble clef
The piano uses both the treble clef and the bass clef.
treble clef
Bass clef.
A major 2nd below A is G.