Innate immunity had two components first line of defence and second line of defence. Which one of the following is not second line of defence?

Innate immunity had two components first line of defence and second line of defence. Which one of the following is not second line of defence?

فطری استثنیٰ کے پاس دفاع کی پہلی لائن اور دفاع کی دوسری لائن تھی۔ مندرجہ ذیل میں سے کون سا دفاع کی دوسری لائن نہیں ہے؟
Explanation

Mucus is part of the first line of defense (physical barrier).

The second line includes fever, WBCs, and chemical responses after pathogens enter the body.