Upon exposure to $UV$ radiation,$DNA$ stained with ethidium bromide will show:

Given below are four statements pertaining to the separation of $DNA$ fragments using gel electrophoresis. Identify the incorrect statements:
$(a)$ $DNA$ is a negatively charged molecule and so it is loaded on the gel towards the Anode terminal.
$(b)$ $DNA$ fragments travel along the surface of the gel,whose concentration does not affect the movement of $DNA$.
$(c)$ The smaller the size of the $DNA$ fragment,the larger is the distance it travels through it.
$(d)$ Pure $DNA$ can be visualized directly by exposing it to $UV$ radiation.
Choose the correct answer from the options given below:

In which method is recombinant $DNA$ directly injected into the nucleus of an animal cell?

Which of the following is not used in the Southern hybridization technique for chromosomal $DNA$ analysis?

Which one of the following statements is not true regarding the gel electrophoresis technique?

Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign $DNA$ in addition to a selectable marker?