Define and explain: Active immunity and Passive immunity.

(N/A) Active 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. It is slow and takes time to give its full effective response.
Passive immunity: When ready-made antibodies are directly given to protect the body against foreign agents,it is called passive immunity. This provides immediate relief,for example,the administration of tetanus antitoxin or antibodies received by a fetus from the mother through the placenta.