試題詳解

53. Which is not characteristic of all mammals?
(A) having glands to produce nourishing milk for offspring
(B) giving birth to live young (viviparous)
(C) a four-chambered heart that prevents mixing of oxygenated and deoxygenated blood
(D) having a diaphragm to assist in ventilating the lungs
(E) having hair during at least some period of life