Explain how and why the blue-white screening method helps to identify vectors that have successfully taken up a DNA insert during cloning. Provide as much detail as you can. You do not need to actually solve the equation, since I assume you haven't got a calculator. In the usual convention we have adopted for writing double-stranded DNA sequences, which ends are 5' and which are 3'. A circular piece of DNA can be made linear by the action of a restriction enzyme.
Ligation can lead to many different products.