When your body is infected with the cold virus, antibodies tag the pathogen’s which are found on their outer surface, for destruction by immune cells.

The given blank can be filled with antigens.

Explanation:

The immune system safeguards the body from probable harmful components by identifying and reacting towards the antigens. The antigens are the components generally the proteins found on the surface of the viruses, cells, or bacteria.  

The non-living components like the chemicals, drugs, toxins, and foreign substances like splinter can also be the antigens. The immune system identifies and eradicates, or attempts to destroy the components, which comprise antigens.  

that would be called plucking : )

explanation:

''plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large "joint blocks". as a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock."