The correct answer is (c) discover antigens in body fluids.
B lymphocytes act as antigen presenting cells that recognizes and displays the antigen to the white blood cells. These cells process the antigens that are present in body fluids. Professional antigen presenting cells includes B-lymphocytes, macrophages, dendritic cells, etc.
What is the type of sunflower, and how fast does it use photosythesis?
Answer:
Option D, Gastric Juices
Explanation:
The second line of defense is a non specific defense mechanism in which no specific individual is targeted but all invaders are killed in general way. Some common mode of second line of defense are - Phagocytic cells (white blood cells), inflammatory responses, macrophage system etc. The second line of defense comes into action when the invader has surpassed the first line of defense which include either physical barrier like skin, mucous membrane, hair, cilia etc. or chemical barriers like gastric juices, saliva, Hyaluronic acid etc.
Hence, gastric juice does not belong to second line of defense.
Thus, option D is correct.
