Which restriction enzyme produces blunt ends upon cleavage?

Polyethylene glycol method is used for

Identify the $DNA$ segment which is not a palindromic sequence.

Which of the following enzymes are used to join bits of $DNA$?

$I.$ $Ori$ also controls the copy number of the linked $DNA$.
$II.$ If a foreign $DNA$ ligates at the $BamHI$ site of the tetracycline resistance gene in the vector $pBR322$,the recombinant plasmid loses the tetracycline resistance due to the insertion of foreign $DNA$.
Choose the correct option regarding the above statements.

The first restriction endonuclease type $II$,$...A..$,was isolated by Smith,Wilcox and Kelley from $...B...$ bacterium. It was found to cut $DNA$ molecules at a particular point by recognizing a specific sequence of six base pairs,known as the $...C....$. Here $A, B$ and $C$ can be: