Distinguish between Arabs and Muslims. Abraham (or Ibrahim) is indeed the legendary ancestor of the Arabs, through his illegitimate son Ishmael, as he is the ancestor of the Jews through his legitimate son Issac. As Ishamael was the older, the Arabs/Muslims tend to gloss the illegitimacy and insist that Ishmael, not Isaac, was the one all the stories are about (e.g., was the one NOT sacrificed to prove Abraham's devotion). In fairness, Ishmael wasn't "illegitimate" in the same sense that Europeans would think of it; although Abraham wasn't married to Ishmael's mother, Hagar, he was entitled to have children with her as she was his wife's "handmaiden" or slave.
to a man named Abraham (אברהם)
Abraham
All dogs can trace their ancestry back to the wolf.
The Christians and the Moslems (as well as the varety of sects within each religion) claim to be descendants of Abraham, at least in terms of philosophy and ethics. However, only the Jews actually trace, or at least try to trace, their personal ancestry back to Abraham
Han
England.
Abraham Lincoln
Their ancestry trace back to thousands of years BCE, long before the Europeans came in.
No one worships Abraham, however, he is significant to Jews, Christians and Muslims. All three faiths can link themselves back to Abraham.
They were born in the colonies but could trace ancestry back to England and the British Isles.
Your heritage goes all the way back to the very very beginning. However, no one is able to trace their ancestry that far, and few are able to trace back more than a 200 years or so.
Prophet Abraham (or Ibrahim in Arabic)