Answer:
Look into my face and I'm everybody. Scratch my back and I'm nobody.
My first is twice in apple but not once in tart. My second is in liver but not in heart. My third is in giant and also in ghost. Whole Iβm best when I am roast.
I run around the city, but I never move.
When the horse strokes the cat, the wood begins to sing.
You must keep this thing. Its loss will affect your brothers. For once yours is lost, it will soon be lost by others.
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?