Agarose,extracted from seaweeds,is used in:

What is a plasmid?

Which of the following statements are not true regarding restriction endonucleases?
$A$. They are called molecular scissors.
$B$. These are the enzymes responsible for restricting the growth of bacteriophages in $E. coli$.
$C$. They cut the $DNA$ only at the centre of the palindromic sites.
$D$. They remove nucleotides only from the ends of $DNA$ fragments.
$E$. They recognise specific palindromic base-pair sequences.
Choose the answer from the options given below:

$DNA$ ligase is an enzyme that .......

$A$ single-stranded piece of nucleic acid tagged with a radioactive molecule,which is used to detect a specific gene through hybridization,is called:

$BACs$ and $YACs$ are . . . . . . .