Question

QUESTION 9 A disease-causing microorganism or virus is referred to as a(n) avirulent infection. colony. commensal. pathogen.

Answer 1

Answer.

9-D) Pathogen

Explanation:

Pathogens are terms used for organisms that cause diseases in host. They can vary from small bacteria , viruses to single celled or multicellular eukaryotes.

10-B) Attach to the host

Explanation: The first step for establishment of infectiom is attachment of pathogen with the host surface that takes place by the help of receptor and ligand. receptors are macromolecular binding sites on host's surface that binds with ligands on pathogens surface .

11- C) - five

Explanation: There are five classes of antibody that is IgA, IgD, IgE , IgM, IgG. They all are distinguished from each other on the basis of heavy chain present in their structure.

12- B) classical pathway

Explanation: The classical complement pathway is initiated by the antigen antibody complex that makes use of antibody IgG , IgM which is bound to antigens .

Alternative pathway is activated by other factors like activation of C3, factor D etc.

So, the pathway that requires Antibodies to be activated is classical complement pathway.