To which charge is a $DNA$ molecule translocated during gel electrophoresis?

Study the given figure carefully and select the correct statements regarding this.
$I.$ It represents typical agarose gel electrophoresis showing differential migration of $DNA$ fragments.
$II.$ Lane $1$ contains undigested $DNA$ fragments.
$III.$ Lanes $2$ to $4$ contain digested $DNA$ fragments.
$IV.$ Smallest $DNA$ bands are present at $(A)$ position and largest $DNA$ bands are present at $(B)$ position.

Palaeontologists unearthed a human skull during excavation. $A$ small fragment of the scalp tissue was still attached to it. Only a little $DNA$ could be extracted from it. If the genes of the ancient man need to be analysed,the best way of getting a sufficient amount of $DNA$ from this extract is:

In a bioreactor,through which system can a small volume of culture be withdrawn periodically?

From the following tools/techniques of genetic engineering,identify those which are required for cloning a bacterial gene in animal cells and choose the correct option:
$I$. Endonuclease $II$. Ligase
$III$. $A. tumefaciens$ $IV$. Microinjection
$V$. Gene gun $VI$. Lysozyme
$VII$. Cellulase $VIII$. Electrophoresis

Stirred-tank bioreactors have been designed for