Hayat Ashraf

Immunity refers to the body's ability to defend itself against harmful substances, pathogens, and foreign invaders, thereby protecting the body from various diseases. It is a complex system involving various organs, cells, and molecules working together to recognize and eliminate potentially harmful agents. There are two main types of immunity in the human body: 1. Innate Immunity:    Innate immunity is the first line of defense against pathogens and foreign substances. It is a non-specific form of immunity that provides immediate protection. Innate immunity is present from birth and does not require previous exposure to a specific pathogen to be activated. Some key components of innate immunity include:     Physical Barriers: Skin, mucous membranes, and other physical barriers prevent pathogens from entering the body.    Chemical Defenses: Enzymes and chemicals in body secretions (e.g., tears, saliva, stomach acid) can kill or inhibit the growth of pathoge...