Which of the following is used as a cloning vector in higher organisms?

In recombinant $DNA$ technology,a vector is defined as .....

Select the appropriate option for $Agrobacterium$ $tumefaciens$.

$PCR$ technique was invented by

Given below are two statements:
Statement $I$: Plasmids are autonomously replicating $DNA$.
Statement $II$: Plasmids are extrachromosomal $DNA$.
In the light of the above statements, choose the correct answer from the options given below:

Which of the following is used to stain separated $DNA$ fragments so that they can be visualized?