Column I lists the components of body defence and column II lists the corresponding descriptions. Match the two columns. Choose the correct option from those given.
Column IColumn IIA. Active natural immunity1. Injection of gamma globulinsB. First line of defence2. Inflammation and phagocytosisC. Passive natural immunity3. Direct contact with the pathogens that have entered insideD. Second line of defence4. Surface barriers5. Antibodies transferred through the placenta
Active immunity develops in a body on being exposed to a live pathogen. Here, the pathogen establishes an infection, which is then subdued in time and the immunity is built due to the formation of memory cells. Naturally acquired passive immunity occurs during pregnancy, in which certain antibodies are passed from the maternal blood into the foetal bloodstream through the placenta. Our body has a two-line defence system against pathogens. The first line of defence against pathogens are the surface barriers like the skin, and others like tears, saliva, etc. If the pathogens are able to get past the first line of defence, for example, through a cut in your skin, and an infection develops, the second line of defence becomes active. Through a sequence of steps called the immune response, the immune system attacks these pathogens. Inflammation and phagocytosis are a part of the second line of defense.