Recombinant $DNA$ has an integrated fragment of:

Refer to the following statements for agarose-gel electrophoresis :
$(a)$ Agarose is a natural polymer obtained from sea-weed.
$(b)$ The separation of $DNA$ molecules in agarose-gel electrophoresis depends on the size of $DNA$.
$(c)$ The $DNA$ migrates from negatively-charged electrode to the positively-charged electrode.
$(d)$ The $DNA$ migrates from positively-charged electrode to the negatively-charged electrode.
Choose the most appropriate answer from the options given below :

Restriction enzymes are isolated chiefly from:

Which of the following can be considered as molecular scissors?

Nowadays, which of the following are known as "magic circles"?

Which of the following is an incorrect pair regarding the tools of recombinant $DNA$ technology and their uses?