Which method is used to amplify a desired gene in large numbers?

The significance of the heat shock method in bacterial transformation is that it facilitates:

What is the ultimate objective of $r-DNA$ technology?

You have identified a useful gene in bacteria. Make a flow chart of the steps that you would follow to transfer this gene to a plant.

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:

Which of the following method$(s)$ is used to introduce foreign $DNA$ into host cells?