取两只大小相同的活蝗虫，将甲蝗虫的头部朝下并让其头部浸没在水中，让乙蝗虫的头部朝上并将其胸、腹部浸没在水中，结果是（ ）
A．甲蝗虫先死亡
B．乙蝗虫先死亡
C．两只蝗虫同时死亡
D．两只蝗虫都不会死
在蝗虫腹部第一节的两侧，有一对半月形的薄膜，是蝗虫的听觉器官，在左右两侧排列得很整齐的一行小孔，就是气门．从中胸到腹部第8节，每一个体节都有一对气门，共有10对，每个气门都向内连通着气管．在蝗虫体内有粗细不等的纵横相连的气管，气管一再分支，最后由微细的分支与各细胞发生联系，进行气体交换．因此，气门是气体出入蝗虫身体的门户，但真正进行气体交换的部位是气管．所以蝗虫甲的头部浸没在水中，能进行呼吸，没有死，而蝗虫乙胸腹部浸没在水中只露头的，无法与外界进行气体交换而窒息而死．
故选：B
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| "I'm too old and it's too late," which played over and over in my mind. I was 1 and exhausted after ending my marriage and my law career at the same time. 2 my ambition to become a writer, I 3 my ability to succeed as one. Had I wasted years going 4 the wrong goals? I was at a low point 5 the voice on the radio began 6 the story of Grandma Moses. Ann Mary Moses left home at thirteen, bore ten children and worked hard to raise the five who 7 . Struggling to make a living on poor farms, she managed to 8 a bit of beauty for herself by embroidering (绣花) on cloth. At seventy-eight, her fingers became 9 awkward to hold a needle. 10 give in to aging, she went out to an empty room and began to 11 . For the first two years, these paintings were either given away or sold 12 a little money. But at the age of seventy-nine, she was "discovered" by the 13 world-and the rest is 14 . She went on to produce more than two thousand paintings, 15 her book illustrations (插图) for It was the Night before Christmas were completed in her one-hundredth year! 16 I listened to the radio, my 17 changed. If Grandma Moses 18 begin a new career and succeed after eighty, my life still had 19 after thirty. Before the program ended, I rushed to my computer to work on the novel I'd nearly 20 . It was published eight months later. | ||||
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