题干

对某成年男性色盲患者睾丸内一正处于减数第二次分裂后期的细胞的描述,正确的是

A:细胞内有23条染色体,其中22条常染色体,1条性染色体,可能没有色盲基因

B:细胞内有46条染色体,其中44条常染色体,2条Y染色体,有一个色盲基因

C:细胞内有46条染色体,其中44条常染色体,2条X染色体,有2个色盲基因

D:细胞内有46条染色体,其中44条常染色体,1条X染色体,1条Y染色体,有1个色盲基因

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答案(点此获取答案解析)

C

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完形填空

    I fell in love with Yosemite National Park the first time I saw it, when I was 13. My parents took us there for camping. On the way out, I asked them to wait while I ran up to E1 Capitan, a1 rock of 3,300 feet straight up. I touched that giant rock and knew 2 I wanted to climb it. That has been my life's passion (钟爱) ever since—3 the rocks and mountains of Yosemite. I've long made Yosemite my 4.

    About 15 years ago I started seeing a lot of 5 like toilet paper, beer cans, and empty boxes, around the area. It's6 me why visitors started respecting the place 7 and treated such a beautiful home-like place this way.

    I tried 8 trash (垃圾) myself, but the job was too big. I would9 an hour or two on the job, only to find the area trashed all over again weeks later. Finally, I got so 10 it that I decided something had to change.

    As a rock-climbing guide, I knew 11about organizing any big event. But in 2014, together with some climbers, I set a date for a 12. On that day, more than 300 people 13 Over three days we collected about 6,000 pounds of trash. It was amazing how much we were able to14 I couldn't believe the15we made —the park looked clean!

    Each year volunteers come for the cleanup from everywhere. In 2016 alone, 2,945 people picked up 42,330 pounds of trash and16132 miles of roadway.

    I often hear people17about their surroundings. If you are one of them, I would say the only way to change things is by 18rather than complaining. We need to teach by 19.You can't blame others 20 you start with yourself.