The image below depicts the result of gel electrophoresis.

If the ladder represents sequence length upto 3000 base pairs (bp).
a. Which of the bands (I - IV) correspond to 2500 bp and 100 bp respectively?
b. Explain the basis of this kind of separation and also mention the significance of this process.

A circular plasmid of 10,000 base pairs (bp) is digested with two restriction enzymes, A and B , to produce a 3000 bp and a 2000 bp bands when visualized on an agarose gel. When digested with one enzyme at a time only one band is visible at 5000 bp. If the first site for enzyme a(A1) is present at the 100^(th) base, the order in which the remaining sites (A2,B1 and B2 ) are present is-

Match the terms given in column I with their definitions in column II and select the correct answer from codes given below. {:(Column I,Column II),(A."Transformation",(i)"Sequences cut by restriction enzymes"),(B."Recognition site",(ii)"Process by which DNA fragments are separated based on their size"),(C."Gel electrophoresis",(iii)"Plasmid DNA that has incorporated human DNA"),(D."Recombinant DNA",(iv)"Process by which bacteria take up pieces of DNA from the environment"):}