The correct answer is option A.
The immune system safeguards the body against the probable harmful materials by reacting and determining the antigens. Antigens are the components situated on the surface of viruses, cells, bacteria, or fungi. The immune system destructs and determines, or attempts to destroy the components, which comprise antigens.
Nonspecific or innate immunity is the defense system with which an individual is born. It safeguards the person against all the antigens. Innate immunity includes barriers, which keep the harmful substances from getting inside the body. These barriers make the first line of defense in the immune reaction.
