(Question)
Q: Blood calcium levels are tightly regulated by the what system? Choices: - digestive - cardiovascular - nervous - endocrine A:
(Answer)
endocrine

(Question)
Q: What organ systems link exchange surfaces with cells throughout the body? Choices: - vascular - pulmonary - nervous - circulatory A:
(Answer)
circulatory

(Question)
Q: A rusty bike has been left outside in damp weather too many times, so the iron in the metal parts have? Choices: - melted - eroded - decayed - rusted A:
(Answer)
rusted