问题
选择题
用乳酸菌制作泡菜时，要用水密封，这是为了提供 [ ]
A．安静的环境
B．有氧的环境
C．无氧的环境
D．防止细菌逃跑
答案
答案：C
搜题请搜索小程序“爱下问搜题”
用乳酸菌制作泡菜时，要用水密封，这是为了提供 [ ]
A．安静的环境
B．有氧的环境
C．无氧的环境
D．防止细菌逃跑
答案：C
| 阅读以下文字，完成以下问题。 1988年，一位爱好飞蛾的美国医生，发表了一篇科学论文，论述了夜晚的灯光是如何影响飞蛾的。这是一篇很普通的文章，但在当时，这也是一篇最明确地指出人造光会对动物产生危害的文章，一些针对人造光与动物关系的研究由此产生了。 在美国的佛罗里达海岸，城市的灯光曾造成刚破壳而出的小海龟迷路，使一些小海龟忽然爬向错误的方向，引导小海龟踏上了死亡之途。在很多场合下，即使动物们不直接暴露于灯光之下，它们也难以摆脱光污染的伤害，城区里的灯光会通过云层反射下来，使夜空处在非自然的光亮下，科学家们称这种情形为天空赤热。 最早指出天空赤热危害的是天文学家，因为这种光现象极大阻碍了他们对星空的观测。佛罗里达的科学家迈克尔•萨曼认为，钠灯也许可以成为城市的新光源。钠灯释放一种特殊的黄色波长，天文观测时，这种光波对观测的影响相对较小，而且对海龟和飞蛾之类的动物也不会造成伤害。萨曼说，海龟也许根本看不见钠灯，即使看见了，这种频率的光波也不会对它们的方向判断造成混乱。 然而，钠灯并不是万用良方。对于有些动物而言，钠灯的黄色光波和其他灯光的光波并无差异，有时甚至比传统的灯光显得更糟。突然暴露于灯光中的青蛙会延缓它们的进食和生殖行为，在黄光和红光下，火蜥蜴甚至无法从一个地方移动：到另一个地方。灯光的照射使水生无脊椎动物在夜间的活动量减少，其后果就是减少了这些无脊椎动物对藻类的消耗，造成藻类的恶性繁殖，水质下降。灯光还可能对鸟类的磁场定位系统造成扰乱，使这些鸟儿时常迷失在电视塔的附近。灯光可以削弱飞蛾的防御反应，使飞蛾在遇到危险时失去逃跑能力。 [ ]是那些有能力适应人造光的动物，它们在进化的过程中也不得不付出生物学的代价：某些异常的品质受到奖赏，[ ]在正常的自然状态下，它们[ ]变得不适应了。从逻辑上说，这样的进化选择将导致动物渐渐适应永恒的光照环境，并进化一些新的品质，它明显不同于在黑暗环境中生存的野生动物。假若让正常状态下和非正常状态下的这种动物交配繁衍，那将给这种动物带来灭绝的危险。 也许，我们的确到了找回那片失落星空的时候了。 |
下列有关光污染的表述，说法正确的一项是( )。
A．人类对光污染的研究是从1988年开始的
B．人造光既减少水生无脊椎动物的活动量，又造成水藻的恶性繁殖，水质下降
C．鸟类时常迷失在电视塔附近，可能是因为灯光扰乱了它们的磁场定位系统
D．灯光可以使飞蛾丧失防御能力，在遇到危险时不知道逃跑
Years ago, if a teenager had some problems in his life, he might go home and write in his diary; now, a teenager with 26 problems might go onto the Internet and write about them in a blog（博客）．In many ways, a diary and a blog are very 27 ．But what makes blogging different from writing in a（n） 28 diary? The biggest difference is that a blog is much more 29 than a diary. Usually, a teenager treats his diary like a book full of 30 that he does not want to 31 with others. It’s interesting that someone who writes in a blog 32 a diary will probably write nearly the same information. I have a little sister, and sometimes I go online to read her 33 . She writes about things like waking up early for swimming practice and not studying enough for her chemistry test. 34 I was her age, I wrote about the same things, but 35 in my dairy. Then, after I had finished writing, I would hide my diary in a secret place because I was 36 that my sister might read it. The biggest 37 with blogging is that anyone can read what you write. If I was angry with a friend during high school and wrote something 38 about him in my diary, he would never know. 39 , if my sister ever wrote something bad about a friend, that friend might 40 her blog and get angry. There are also 41 to blogging, of course. If I was feeling sad one day and wrote in my diary, “ Nobody cares about me”, because no one would 42 about it. However, if my sister wrote the same sentence in her blog, her best friends would quickly 43 and tell her how much they 44 her. Blogs help people 45 in contact with their friends and know what the people around them are doing.
|