In case of immunity, the first line of body defense is:
Correct answer: D. Skin
- A. Macrophages
- B. Lymphocytes
- C. Blood cells
- D. Skin
Explanation
The correct answer is skin. The skin acts as a physical barrier, preventing harmful pathogens from entering the body. It is the first line of defense in the immune system. The skin also hosts beneficial bacteria that help maintain a balance, preventing the growth of harmful microorganisms.Macrophages operate in the second line of defense, dealing with pathogens that have bypassed the first line. Lymphocytes are part of the adaptive immune system, responding to specific invaders after they have breached initial defenses. Blood cells, while crucial for various bodily functions, are not involved in the initial immune barrier.
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About Specific Defense Mechanism
Specific defense mechanisms provide targeted immunity through B lymphocytes, T lymphocytes, antibodies and memory cells that recognize particular antigens. Questions cover humoral and cell mediated responses, clonal selection, primary and secondary immune responses, vaccination and passive immunity, while distinguishing adaptive defenses from the immediate, non specific innate response.
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