Skin and mucous membranes are part of the body defense system and they form the:
Correct answer: A. Physical barrier
- A. Physical barrier
- B. Mechanical barriers
- C. Chemical barriers
- D. Biological barriers
Explanation
First defense line is physical as well as chemical barrier but skin and mucous are physical barrier as they are not involve in chemical reaction and protect body from external particles and it is strong defense line .
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The circulatory system covers the chambers, valves and conducting pathway of the human heart, along with the cardiac cycle and control of heartbeat. It compares arteries, veins and capillaries by structure and function, and explains how the lymphatic system returns tissue fluid, transports absorbed fats and supports immunity.
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