Re: humanity spread from Adam and Eve?
I might start guessing too but if u want to hear the traditional view then it is that Hoor al Ein were sent by Allah SWT to be paired with Habeel and Qabeel and the human reproduction started to take place…here is a few references for u if u r interested in researching this…
Mustadrak Al-Wasael by Al-Noori, vol. 14, pg. 362.
Behar Al-Anwar by Al-Majlisi, vol. 11, pg. 227-28.
Qasas Al-anbia by Al-Jaza’eri, pg. 65-66.