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.
Answer:
Some challenges animals might face when migrating are disease, global climate change, overexploitation, and habitat destruction.
Explanation:
In virtually every corner of the globe, migratory animals face a growing array of threats, including habitat destruction, overexploitation, disease, and global climate change. Saving the great migrations will be one of the most difficult conservation challenges of the 21st century.
That would be the chloroplasts. They are small cells in a leaf that store chlorophyll.
