It is in the Quran in many versus Allah the almighty has indicated the reasons of creations particularly human being why he created and how he created and all that, mainly to answer your question is to identify each other from person to another person as one of the criterion in the creation itself. I may pose like this 100 question looks like logical one but not answerable by many by scientific wisdom except such things has to be connected relegius ties i.e faith in unseen as well as faith in Divinity which can be only convinced by referring to divine doctrines.
It is in the Quran in many versus Allah the almighty has indicated the reasons of creations particularly human being why he created and how he created and all that, mainly to answer your question is to identify each other from person to another person as one of the criterion in the creation itself. I may pose like this 100 question looks like logical one but not answerable by many by scientific wisdom except such things has to be connected relegius ties i.e faith in unseen as well as faith in Divinity which can be only convinced by referring to divine doctrines.