Which of the following range of temperature is required for denaturation,annealing of primer,and primer extension of $PCR$ respectively?

Explain $PCR$ in short.

Which of the following statements are correct with respect to $DNA$ separation, isolation and visualization?
$A$. The cutting of $DNA$ is done by molecular scissors.
$B$. The $DNA$ fragments separate according to their size in an agarose gel, upon electrophoresis.
$C$. The separated $DNA$ fragments can be seen without staining when exposed to $UV$ light.
$D$. The separated $DNA$ fragments, when stained with ethidium bromide, can be seen in visible light.
Choose the correct answer from the options given below:

Following enzymes/chemical/technique are used in the process of gel electrophoresis:
$I.$ sample $DNA$ is cut into fragments
$II.$ restriction endonucleases
$III.$ agarose gel
$IV.$ ethidium bromide
$V.$ $UV$-radiation
$VI.$ elution
Mark the correct sequence of their use.

Which of the following cannot be used for direct gene transfer?

Identify the diagram given below.