Gene gun method is used to introduce alien DNA into host cells where the  DNA fragments are  coated on to microparticles of  _______.

In gene gun method, microparticles of tungsten or gold are used to introduce alien DNA into the host cells. It is a physical method devised to introduce DNA into plant cells containing cell walls.

(1), (2) and (3) Microparticles of silver, copper or zinc are not used in the gene gun method.