What is the term for immunization through the injection of preformed antibodies?

Passive immunization

The correct answer is Option (2) -Passive immunization

Passive immunization refers to the administration of preformed antibodies directly into the body to provide immediate protection against specific pathogens or toxins. These antibodies are obtained from a donor who has already developed immunity to the target antigen. The injected antibodies provide temporary protection and do not stimulate the body's immune system to produce its own antibodies.

When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.  The yellowish fluid colostrum secreted by mother during the initial days of lactation has abundant antibodies (IgA) to protect the infant. The foetus also receives some antibodies from their mother, through the placenta during pregnancy. These are some examples of passive immunity.

When a host is exposed to antigens, which may be in the form of living or dead microbes or other proteins, antibodies are produced in the host body. This type of immunity is called active immunity. Active immunity is slow and takes time to give its full effective response.

Innate immunity is non-specific type of defence, that is present at the time of birth. This is accomplished by providing different types of barriers to the entry of the foreign agents into our body.