In gene gun method the cells are bombarded with high velocity micro particles of which substance?

Both I and II

The correct answer is Option (4) -Both I and II

There are several methods to introduce alien DNA into host cells. One such method is micro-injection, where recombinant DNA is directly injected into the nucleus of an animal cell.In another technique, suitable for plants, cells are bombarded with high-velocity micro-particles of gold or tungsten coated with DNA. This method is known as biolistics or gene gun.

Biolistics: Biolistics is a method of introducing foreign DNA into host cells, particularly plant cells, using high-velocity micro particles. In this technique, small particles, such as gold or tungsten, are coated with the desired DNA and then shot into the target cells using a device known as a gene gun. The high velocity of the particles allows them to penetrate the cell wall and deliver the DNA into the host cell's nucleus.