Nearly all functional units of the immune system are adversely affected by which of the following ...

Nearly all functional units of the immune system are adversely affected by which of the following mineral deficiencies?
 A) zinc
  B) magnesium
  C) fluorine
  D) copper

---

Which of the following statements is false?
 A) All preganglionic neurons of the parasympathetic nervous system release acetylcholine.
  B) All motor neurons of skeletal muscles release acetylcholine.
  C) All postganglionic neurons of the sympathetic nervous system release acetylcholine.
  D) All postganglionic neurons of the parasympathetic nervous system release acetylcholine.