Which of the following statements about physiological regulation and processes are true? Provide brief explanations for each.

b) The correct option is (iii). Saliva secretion is primarily regulated by the nervous system (autonomic nervous system), not by hormones. Other secretions like steapsin, bile, and gastric juice are under hormonal control. c) The correct option is (i). Chief cells (also called peptic cells) in the stomach produce pepsinogen, which is the inactive precursor to pepsin. d) The correct option is (i). When an axon is stimulated, sodium ions (Na^+) rush into the cell, causing the inside of the membrane to become temporarily positive relative to the outside. This is known as depolarization during an action potential. e) The correct option is (iii). The oxygen dissociation curve of hemoglobin is typically sigmoid (S-shaped), reflecting the cooperative binding of oxygen to the four heme groups. f) The correct option is (ii). At high carbon dioxide tension (high pCO_2), the blood becomes more acidic. This decrease in pH reduces hemoglobin's affinity for oxygen, causing the oxygen dissociation curve to shift to the right. This is known as the Bohr effect, which facilitates oxygen release to tissues. g) The correct option is (i). Calcium ions (Ca^2+) are crucial cofactors required for several steps in the blood coagulation cascade, including the activation of various clotting factors. Send me the next one 📸