Yes, but when you reach the stage of "because!" the answer is not really "because!"; the real answer is: "because no one has ever observed otherwise and no one can think of any plausible way that it could be otherwise!"
well, it also can mean:
1. "I don't know, so quit bugging me."
2. "No one knows, because the web of causality is too big and complicated and old to ever trace back to the ultimate roots or describe in detail all the way from the root through all its permutations to the event about which you are bugging me."
3. "I'm bigger and stronger than you are, and I'll mulch you if you keep bugging me, so there!"