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
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統計: A(7), B(18), C(4), D(8), E(12) #2189365
統計: A(7), B(18), C(4), D(8), E(12) #2189365