Look up "Mitochondrial Eve". Your second question is one of the largest causes of debate and division among Christians, and in many ways unresolved so I won't attempt to answer at any length (I'm far from being a Bible scholar or anything near it). All I will say is that firstly the "Bible", as we refer to it, is not a book. It is a collection of books, books from all varieties of literary genres; poetry, historical, prophetic, fictional, etc. Therefore not all parts of it are in any way intended to be scientifically or historically accurate, but simply speaking of a deeper spiritual truth.
We also need to approach the Bible with the eyes of faith, not with eyes of criticism. For me, one of the greatest ways to read the Bible is in light of the Gospel, i.e. to see the foreshadowing of Christ in the Old Testament. Not seen through the lens of Christ, the OT can certainly be a minefield of confusion. So before anything else, I would encourage the person to pray; to pray for faith and to pray for a real experience of Christ. "Ask and you shall receive".
With Christ in our hearts and the Spirit guiding us, the Bible takes on a new life, speaking not just of past events, but speaking into our own lives with real meaning and power.
We also need to read it with an awareness of the context; Who wrote what we are reading? Why? What was the world/circumstances they were living in at the time of writing? For whom were these things written?
Can we bend the Bible to meet the evidence? In some ways, we can, actually. For example, the seven days of creation. Most Christians would accept that God did not
literally make the universe and everything in it in seven literal earth-days as we know them. It is just given as a relatable period of time. You could say "In the first period of time God created......". How far this can be taken however, is up for debate.