题干

群落中的不同种群间存在着多种多样的关系,这些种间关系可用不同的曲线表示出来.请判断下列有关三种曲线图的说法中正确的是(    )

A:鹰与鼠的种间关系可用图①表示,其中曲线a表示鹰种群的数量变化

B:T2噬菌体与细菌的种间关系可用图①表示,二者分开一方有利

C:大豆与根瘤菌的种间关系可用图②表示,二者分开彼此有利

D:在同一个牧场的牛和羊的关系可用图③表示,曲线a代表占优势者

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D

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    I don't think there is anything more important than health. “Health is the greatest wealth,” wise people say. You can't be good at your studies or work well when you are ill.

    If you have a headache, toothache, backache, earache or bad pain in the stomach, if you complain of a bad cough, if you run a high temperature and have a bad cold, or if you suffer from high or low blood pressure, I think you should go to the doctor. The doctor will examine your throat, feel your pulse, test your blood pressure, take your temperature, sound your heart and lungs, test your eyes, check your teeth or have your chest X-rayed. After that, he will advise some treatment, or some medicine. The only thing you have to do is to follow his advice.

    Speaking about doctor's advice, I can't help telling you a funny story. An old gentleman came to see the doctor. The man was very ill. He told the doctor about his weakness, memory loss and serious problems with his heart and lungs. The doctor examined him and said there was no medicine for his disease. He told his patient to go to a quiet place for a month and have a good rest. He also advised him to eat a lot of meat, drink two glasses of red wine every day and take long walks. In other words, the doctor advised him to follow the rule: "Eat with pleasure, drink with pleasure and enjoy life as it is." The doctor also said that if the man wanted to be well again, he shouldn't smoke more than one cigarette a day. A month later the gentleman came into the doctor's office. He looked cheerful and happy. He thanked the doctor and said that he had never felt a healthier man." But you know, doctor," he said, “it's not easy to begin smoking at my age.”