Which one of the following causes crown gall disease?

The thermostable enzymes $Taq$ and $Pfu$ are isolated from thermophilic bacteria,which are used as:

The characteristics of a molecular probe are
$I.$ very long molecule
$II.$ double-stranded
$III.$ $DNA$ or $RNA$
$IV.$ complementary to a part of the desired gene
The correct pair is

Molecular scissors are known as .....

The introduction of $T-DNA$ into plants involves

There is a restriction endonuclease called $Eco RI$. What does "co" part in it stand for?