Why are blood leukocytes considered “protectors” of a person?

1) leukocytes, according to I.I. Mechnikov, – phagocytes, i.e. eaters of foreign proteins, microorganisms, dead cells;
2) leukocytes are involved in the production of antibodies that perform a phagocytic function.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.