CBSE Class 10 Answered

Active aquired immunity -

An example would be immunity which develops after antigens (e.g., microbial pathogens) enter the body by natural processes such as infection and, in response, the body’s immune system forms antibodies. In some cases, the immunity may be life-long as with smallpox, measles, chickenpox, yellow fever etc. In other cases, however, the immunity may be lost after only a few years (e.g., diphtheria, tetanus) or even for lesser period (e.g., influenza, pneumonia.

Passive acquired immunity -

Example - Natural transfer of antibodies from the mother to the foetus across the placenta.