Which of the following key factors makes a plasmid a suitable vector in genetic engineering?

Given below are two statements.
Statement $I$: Restriction enzyme $BamHI$ has its recognition site in $tet^R$ region of $pBR322$.
Statement $II$: $E. coli$ having $pBR322$ with a desired $DNA$ if inserted at $BamHI$ site can grow in medium containing tetracycline.
In the light of the above statements, choose the correct answer from the options given below.

Plasmids are composed of

The enzyme known as restriction endonuclease:

To isolate $DNA$ from fungal cells,bacterial cells,and plant cells,the enzymes required are respectively:

Restriction endonucleases are enzymes which