How is the dna strand held open during dna replication?

Prior to the development of dna fingerprinting, blood type could be used to determine possible parentage. although it might prove someone was not a parent, it could not show if someone was positively the parent, only that he or she might be a parent. which of the following is a true statement that can be made about parentage based on blood typing?

The first generation of offspring from the cross of two parents is called the a.f1 generation b.f2 generation c.short generation d.p generation

What was the impact of the concordat of worms?