Answer:
Adaptive immune defense system consists of lymphocytes like B-lymphocytes and T- lymphocytes. B-lymphocytes provides humoral immunity while T- lymphocytes provide cell-mediated immunity to the body.
99% of lymphocytes circulate freely in the blood and lymph. B lymphocytes differentiate into plasma B cells and B memory cells when interact with antigen presented by T helper cells.
Then plasma cells secrete antibodies in the circulation which binds to extracellular antigens through antigen-binding site. Then the bounded antigen is recognized by receptors present on phagocytic cells. This receptor binds the Fc region of antigen bounded antibody and destroy the antigen by phagocytosis.
This is possible because proteins are created from different combinations of amino-acids. While we only have 20 different kinds of aminoacids, these 20 kinds can create thousands of combinations that we can observe in our bodies and bodies of other mammals as well as other organisms.
gas exchange occurs in the human lungs.
Answer:
Explanation:
Cl = 1s2 2s2 2p6 3s2 3p5
Al = 1s2 2s2 2p6 3s2 3p1
Fe2+ = 1s2 2s2 2p6 3s2 3p6 4s2 3d4
S2- = 1s2 2s2 2p6 3s2 3p6
Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. If all electrons in the particle are paired, then the substance made of this particle is diamagnetic.
S2- is diamagnetic because of its paired electrons in the outermost shell.
