Why do identical twins still have different fingerprints?
Two people can share every gene and still never share a single fingerprint.
Fingerprint ridges form in the womb as the skin on tiny finger pads folds under pressure. That pressure depends on how the hand moves, blood flow, and timing, all of which vary randomly even between twins, so genes set only the rough style, not the exact lines.
Twin brothers in Hanoi who look identical and share a phone still each need their own thumb to unlock their own banking app.
Your fingerprints are partly an accident of how you grew, which is why they are unique to you alone.
It explains why fingerprints work as ID even for twins, and why DNA tests and fingerprint tests answer different questions.
Same DNA, different womb-pressure, so different prints.
Learn the idea and practice English at the same time.