Why is it necessary to have a primer on each side of the dna segment to be amplified?

Charles darwin published his theory of evolution in 1859. in what way foes modern evolutionary theory differ from the theory as proposed by darwin? a) darwin inferred that individuals can evolve, but modern generic science has shown that this is not true. b)darwin inferred that individuals do not evolve, but modern genetic science has shown that this is not true. c)modern science has disproved most of darwin's original theory of evolution, because darwin knew nothing about generations and their role in heredity. d)generic studies have shown that gene expression and other factors operate along with natural selection, but most of darwin's theory has been supported by modern science.

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?

Depending on the organism the number of in a cell may change