B lymphocytes are produced in the bone marrow and get mature in the bone marrow only so the site of B cell maturation is bone marrow, not Peyer's patches. B cells produce antibodies that help in destroying microbes.
Peyer's patches are lymphatic tissue mass which is found especially in the mucosa and submucosa of the ileum. This lymphoid organ has a large number of B lymphocytes which monitors the intestinal bacteria and prevents the growth of pathogenic bacteria in the intestine.
Answer: Mesopotamia, china, indus River Valley, the mesoamerican empires..... in this case, the two rivers are the tigris and Euphrates. Mesopotamia. The name Mesopotamia was given to the middle eastern civilizations that existed between the Euphrates and Tigris Rivers. :)
Metabolic alkalosis would cause slower and shallower breathing which increase carbon dioxide concentrations which in turn are consumed to form carbonic acid which helps decrease the pH.