Question
Biology Question on Immune System
The first line of defence in the immune system is provided by
A
skin and mucous membrane
B
inflammatory response
C
the complement system
D
none of these
Answer
skin and mucous membrane
Explanation
Solution
Skin and mucous membrane are the physical barriers that provide the first line of defence or the external defence. These barriers prevent the entry of microorganisms into the body. Outer tough layer of the skin, the stratum corneum prevents the entry of bacteria and viruses. Mucus secreted by mucous membrane traps the microorganisms and immobilises them.