首页
登录
职称英语
You can tell the age of a tree by【B1】______ its rings, but these records of
You can tell the age of a tree by【B1】______ its rings, but these records of
游客
2023-07-06
16
管理
问题
You can tell the age of a tree by【B1】______ its rings, but these records of a tree’s life really say a lot more. Scientists are using tree rings to learn what’s been happening on the sun’s【B2】______ for the last ten thousand years. Each ring【B3】______a year of growth. As a tree grows, it adds a layer to its trunk, taking up【B4】______ elements from the air. By looking at the elements in the rings from a given year, scientists can tell what elements were in the air that year. Doctor Stevenson is【B5】______one element—carbon-14, in rings from both living and dead trees. Some of the rings go back almost ten thousand years to the end of the Ice Age. When Stevenson followed the carbon-14 trail back in time, he found carbon-14 levels change with the【B6】______ of solar burning. You see the sun has cycles. Sometimes it burns【B7】______ at other times it’s relatively calm. During the sun’s【B8】______ periods, it 【B9】______ charged particles in fast moving streams called "solar winds". The particles【B10】______ the formation of carbon-14 on earth. When there’s more solar wind activity, less carbon-14 is produced. Ten thousand years of tree rings show that the carbon-14 level rises and falls about every 420 years. The scientists concluded that solar wind activity must follow the same cycle. [br] 【B6】
选项
答案
intensity
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2813697.html
相关试题推荐
Fewhumanrecordssurviveforlong,the16000-year-oldPaleolithiccavepai
Fewhumanrecordssurviveforlong,the16000-year-oldPaleolithiccavepai
Fewhumanrecordssurviveforlong,the16000-year-oldPaleolithiccavepai
Fewhumanrecordssurviveforlong,the16000-year-oldPaleolithiccavepai
Youcantelltheageofatreeby【B1】______itsrings,buttheserecordsof
Youcantelltheageofatreeby【B1】______itsrings,buttheserecordsof
Youcantelltheageofatreeby【B1】______itsrings,buttheserecordsof
Youcantelltheageofatreeby【B1】______itsrings,buttheserecordsof
Youcantelltheageofatreeby【B1】______itsrings,buttheserecordsof
Youcantelltheageofatreeby【B1】______itsrings,buttheserecordsof
随机试题
[originaltext]Ifyou’vebeenoncampusforverylong,I’mcertainthatyou’
Didyouknowthatallhumanbeingshavea"comfortzone"regulatingthedist
狭义的历史认识主体是()。A.人类 B.人类社会 C.历史研究者 D.群
党的十九大报告指出,全面依法治国是国家治理的一场深刻革命,必须坚持厉行法治,推进
共用题干 ADoctorintheHouseBrushing
下面四个图形中,只有一个是由上面的四个图形拼合(只能通过上、下、左、右平移)而成
说服教育法的方式有语言文字说服和() A.事实说服B.理论说服
由于气候、流通环节等原因,2011年河北省食品价格上涨12.2%;烟酒价格上涨
(2015年真题)1975年2月,西方十国集团以及瑞士和卢森堡共12个国家的中央
男,65岁,心房颤动及高血压病史5年,糖尿病2型,1年前曾发作言语不利伴肢体活动
最新回复
(
0
)