The word "diffuses" in Para. 3 is closest in meaning to ______.

D
答案；D[试题分析] 词义判断题。[详细解答] 根据上下文，前文讲到肺中的空气压力增加，氮气会diffuses from the lungs to the blood，显然，diffuse应理解为扩散到，只有D意思接近，应为正确答案。