$EcoRI$ is a restriction endonuclease. What does the part "co" represent?

How many of the following restriction enzymes produce blunt ends?
$EcoRI, Hind III, Bam HI, EcoR V, Hind II$

Which restriction enzyme produces blunt ends upon cleavage?

Select the incorrect statement.

About gene gun method:
$I.$ This method is also known as biolistic technique.
$II.$ In this method,cells are bombarded with high-velocity micro-particles of gold or tungsten coated with $DNA$ in plants.
$III.$ Important crop plants like maize,rice,and wheat have now been transformed by this method.
Which of the statements given above are correct?

Restriction enzymes are: