Recombinant $DNA$ technology was discovered by

Genetic engineering is defined as .......

In which of the following methods are both desired and undesired genes introduced into the organism?

What is the fate of a piece of $DNA$ carrying only the gene of interest which is transferred into an alien organism?
$A$. The piece of $DNA$ would be able to multiply itself independently in the progeny cells of the organism.
$B$. It may get integrated into the genome of the recipient.
$C$. It may multiply and be inherited along with the host $DNA$.
$D$. The alien piece of $DNA$ is not an integral part of the chromosome.
$E$. It shows the ability to replicate.
Choose the correct answer from the options given below:

Modified antibiotics are manufactured by the technique of

............. technology is useful in vaccine production.