A person got an infection, he became ill but then he survived. What do you think which of immunity he would have developed?

Explanation

The scenario describes 'active immunity'. 'Active immunity' is when the body itself gets exposed to the antigen to generate an immune response, whereby memory cells are produced which confer long lasting or lifelong immunity against the particular agent. This response may take some time to develop. This differs from 'passive immunity', whereby the person is given externally produced antibodies to combat a certain infection rather than the person's own immune system producing its own antibodies. However, since ready-made antibodies are given, the action is rapid.These may be further divided into 'artificially induced immunity' or 'naturally induced immunity'. In 'artificial active immunity', the immunity is produced by intentionally exposing the individual to antigens in a vaccine (hence the term artificial, since exposure did not occur naturally). 'Naturally-induced active immunity' would involve the person themselves getting exposed to the disease-causing agent, naturally, and not by a vaccine. Likewise, 'artificial passive immunity' would involve injecting the antibodies of some other individual into the patient (which is not a natural process). 'Naturally induced passive immunity' would involve the passage of antibodies from one person to the other via natural means, such as during pregnancy when they pass from maternal blood to fetal blood or during breastfeeding.Since the given scenario describes a person contracting an infection, it is active immunity. And since the person was not described to be vaccinated beforehand nor were they injected with external antibodies, they developed an immune response themselves upon natural exposure to the antigen so, it is 'naturally-induced active immunity'.