Restriction enzymes belong to which class of enzymes?

Which of the following sequences represents a palindromic $DNA$ sequence?

Restriction endonucleases are

$I.$ $Ori$ 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.

Which technique is used to isolate immunoglobulins,cellular enzymes,and $m-RNA$?

What is the large extrachromosomal plasmid found in Agrobacterium tumefaciens that has the ability to induce tumors called?