Which enzyme is responsible for joining the foreign $DNA$ fragment with the 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:

In genetic engineering,the modification of $DNA$ has become possible due to the discovery of .............. .

Which of the following statements is correct regarding the gel electrophoresis technique?

Agrobacterium tumefaciens contains a large plasmid that induces tumors in plants,known as:

Which restriction enzyme produces blunt ends upon cleavage?