Which of the following is used in recombinant $DNA$ technique?

What is the small, circular $DNA$ molecule present in bacterial cells in addition to the main genomic $DNA$ called?

Agarose is a natural polymer extracted from

Eco-$RI$ cuts the $DNA$ between . . . . . . only when the sequence $GAATTC$ is present in the $DNA$.

Given below are two statements:
Statement $I:$
Restriction endonucleases recognise specific sequences to cut $DNA$,known as palindromic nucleotide sequences.
Statement $II:$
Restriction endonucleases cut the $DNA$ strand a little away from the centre of the palindromic site.
In the light of the above statements,choose the most appropriate answer from the options given below:

In $EcoRI$,the letter $R$ stands for: