Question

Passive immunity is defined as immunity:
(a)Inherited from the parents.
(b)Achieved through vaccination.
(c)Acquired through first exposure to the disease.
(d)Achieved through the serum of other animals enriched with antibodies.

Answer 1

The host's ability to fight with the disease-causing organisms that are conferred by the immune system is called immunity. The immunity mediated by the macromolecules such as secreted antibodies and complement proteins found in extracellular fluids is called humoral immunity. Humoral immunity is divided into two types:- Active and Passive.

Complete solution:
Passive immunity is the type of humoral immunity in which readily-prepared antibodies are directly given to protect the body against foreign agents.
The yellowish-fluid colostrum secreted by the mother during the initial days of lactation has abundant antibodies (IgA) to protect the infants.
Through the placenta, the foetus also receives some antibodies from its mother during pregnancy.
Passive immunity can also be achieved artificially when high levels of human or animal antibodies present in the serum are transferred to non-immune individuals.
Some characteristics of passive immunity are:
-It is received passively by the host, and there is no participation of the host's immune system.
-It is conferred by the introduction to ready-made antibodies.
-The immune responses are short-lived and less effective.
-Immunity is effective immediately.
-No immunological memory.
-Von Behring discovered the passive immunization and prepared the anti diptheria serum (ADS), injecting a diphtherial antigen into the sheep.

Additional information:
The other type of immunity is called active immunity.
Active immunity is the immunity produced in the host's body when exposed to antigens in the form of living or dead microbes or proteins.
Some characteristics of active immunity are:
-It is developed actively by the host's immune system.
-It is induced by infections or by contacting the immunogen.
-Immune responses are durable and effective.
-The immunity is developed after a lag period.
-Immunological memory is present.

So, the correct answer is 'Achieved through the serum of other animals enriched with antibodies'.

Note:
Immunity achieved through vaccination is active immunity. In vaccine-induced immunity, a killed or weakened form of microbe or pathogen is introduced into the body. As soon as the immune person contacts the disease in the future, the immune system recognizes it.