Functions of the complement system are: a. Lysis of cell (formation of MAC) b. Opsonization C. induce the production of mediators of inflammation d. All answers are correct NK cells-natural killers - belong to: a. basophils

For the first question, the correct answer is:<br /><br />d. All answers are correct<br /><br />The complement system is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear pathogens and damaged cells from an organism, and it promotes inflammation. The functions of the complement system include:<br /><br />a. Lysis of cell (formation of MAC) - The complement system can directly kill pathogens by forming the membrane attack complex (MAC), which creates pores in the cell membrane, leading to cell lysis.<br /><br />b. Opsonization - The complement system can coat pathogens with complement proteins, which act as opsonins. These opsonins enhance the ability of phagocytes to recognize, engulf, and destroy the pathogens.<br /><br />c. Induce the production of mediators of inflammation - The complement system can activate other components of the immune system, such as the inflammatory response, by inducing the production of various mediators, such as cytokines and chemokines.<br /><br />Therefore, all the options provided are correct functions of the complement system.<br /><br />For the second question, the correct answer is:<br /><br />c. None of the above<br /><br />NK cells, or natural killer cells, are a type of cytotoxic lymphocyte that is crucial to the innate immune system. They are distinct from basophils, which are a type of white blood cell that plays a role in allergic reactions and inflammation. NK cells are known for their ability to recognize and kill virus-infected cells and certain types of tumors without the need for prior sensitization to the target.