Everyoneisprovidedbynaturewithasetoffinger-printsentirelydifferentfromthoseofeverybodyelse.Itisnowacceptedasascientificfactthatnotwopeoplehavethesamefinger-printsThetenfinger-printsofonepersonalwaysdifferfromthecompletesetofanother.Butthatisnotall.Theprintofeachseparatefingerofapersondiffersfromhisprintsofallotherfingersandfromtheprintsofotherfingersintheworld.Someonehascalculatedthechancethataprintmadebyonepersonwillbethesameasaprintmadebyanotherandthecalculationshowsthatthechanceissosmallthatforallpracticalpurpose,itdoesn’texist.Thepolice,therefore,alwaysrecordfinger-prints,ifpossible,theyareanunfailingcluetoidentifywhenoncetheyhavebeenobtained.Finger-printidentificationasitisknownandpracticedtodayisofcomparatively(相当地)recentorigin.ItfirstcametothenoticeofmodernpoliceforcesinIndia.Finger-printswerefoundsovaluabletherethattheywerelateradoptedbythepoliceofothercountries.Theyacceptedaslegalevidenceinacourtoflaw;ifaman’sprintsarefoundonthesceneofthecrime,itistakenforgrantedthathewasthere,thoughwhenandwhyhewasthereareotherquestions.36.Whichofthefollowingbestexpressesthemainideaofthepassage?