Answer:
What instrument can make any sound and be heart, but not touched or seen?
I usually wear a yellow coat. I usually have a dark head. I make marks wherever I go.
I'm very tempting, so its said, I have a shiny coat of red, and my flesh is white beneath. I smell so sweet, taste good to eat, and help to guard your teeth.
Look into my face and I'm everybody. Scratch my back and I'm nobody.
Only one color, but not one size. Stuck at the bottom, yet easily flies. Present in sun, but not in rain. Doing no harm, and feeling no pain.
I am your mother's brother's only brother in law. Who am I?