首页
登录
职称英语
Space is a dangerous place, not only because of meteors (流星) but also becaus
Space is a dangerous place, not only because of meteors (流星) but also becaus
游客
2023-07-30
46
管理
问题
Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth. Light gets through, and this is essential for plants to make the food which we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation but their spacesuits or the walls of their spacecraft, if they are inside, do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem". Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged; the figure of 60 reins has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damagea person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will no be discovered until the birth of deformed children or even grandchildren.
Missions of the Apollo flights have had to cross belts of high amount of rems. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage done by radiation, but no really effective ones have been found so far. [br] According to the first paragraph, the atmosphere is essential to man in that ______.
选项
A、it protects him against the harmful rays from space
B、it provides sufficient light for plant growth
C、it supplies the heat necessary for human survival
D、it screens off the falling meteors
答案
A
解析
问题问的是为什么大气层对人类是至关重要的。文章的第四句说到了大气层屏蔽了大量的外来射线。
转载请注明原文地址:https://tihaiku.com/zcyy/2883081.html
相关试题推荐
Thewriterappliedforthejobbecause______.[br]Whatdoesthewriterrealize
Thewriterappliedforthejobbecause______.[br]Whatwasthewriter’sopinio
Thelithiumbatteriesarebecomingimproperforthecellphonebecause______.[
Thelithiumbatteriesarebecomingimproperforthecellphonebecause______.[
Thelithiumbatteriesarebecomingimproperforthecellphonebecause______.[
[audioFiles]audio_eufm_j01_134(200910)[/audioFiles]A、Becauseshehasnothingel
WhenLaurieAronsonwasover35,shedidnotfeelworriedbecauseshewasunwill
WhenLaurieAronsonwasover35,shedidnotfeelworriedbecauseshewasunwill
WhenLaurieAronsonwasover35,shedidnotfeelworriedbecauseshewasunwill
WhenLaurieAronsonwasover35,shedidnotfeelworriedbecauseshewasunwill
随机试题
Sincetheenergycrisis,thesebigcarshavebecomearealliability.Theycost
IsCollegeReallyWorththeMoney?TheReal
语句中没有通假字的是()A.少益嗜食 B.庄公寤生 C.勿使反 D.花林
Berg平衡量表评定中从坐位站起3分提示A.不用手扶即能独立站起并保持稳定 B
妊娠期妇女治疗口腔疾病的适宜时期是A.妊娠初期(1~3个月) B.妊娠中期(4
A.上或中输尿管点压痛 B.肋脊点、肋腰点压痛及叩击痛 C.肾脏缩小 D.
A.风池 B.肩髃 C.大椎 D.天宗 E.至阳落枕兼背痛者,宜配用(
K线图中,当()低于开盘价时,形成阴线。A.结算价 B.收盘价 C.
房地产开发项目工程设计的基本原则有()。A:合理利用资源 B:尽量压缩成本
化脓性脑膜炎A、糖正常,氯化物升高,蛋白明显下降,细胞数升高,以中性粒细胞为主
最新回复
(
0
)