Question

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 I		Column II
A. Active natural immunity B. First line of defence C. Passive natural immunity D. Second line of defence		1. Injection of gamma globulins 2. Inflammation and phagocytosis 3. Direct contact with the pathogens that have entered inside 4. Surface barriers 5. Antibodies transferred through the placenta

• A. A – 2, B – 3, C – 1, D - 4
• B. A – 3, B – 4, C – 5, D – 2
• C. A – 4, B – 2, C – 5, D – 1
• D. A – 1, B – 5, C – 4, D – 3

Answer 1

The correct option is B A – 3, B – 4, C – 5, D – 2

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 pathgens 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. Inflammattion and phagocytosis are a part of second line of defense.