Answer:
Correct answer is "non specific defenses"
Many types of obstacles hinder biomedical scientists from solving health-related challenges. Money that is needed for researches is one of them and you must cooperate with funding agencies. For innovative work you must think outside the box. Also you need to spend too much time for "paperwork".
When your body is infected with the cold virus, antibodies tag the pathogen’s antigens, which are found on their outer surface, for destruction by immune cells.
Hope this helps!