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
2024-02-07
9
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] 【B9】
选项
答案
throws off
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3429966.html
相关试题推荐
Fewhumanrecordssurviveforlong,the16000-year-oldPaleolithiccavepai
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
随机试题
Thereportshowedusvery(clear)______howtheplanecrashed.clearly根据原句的语法结构,
Agriculturalexpertshavelaunchedalandandwatermanagementprojectinth
下列影响血浆从毛细血管滤过的因素中,不正确的是()。A.毛细血管血压 B.血
女性,62岁,干燥综合征病史15年,近2年来出现进行性呼吸困难、干咳,偶有痰中带
在商业银行持续经营条件下,能够用来吸收损失的资本工具有()。A.超额贷款损
副交感神经兴奋时A.心率减慢 B.瞳孔缩小 C.胃肠运动加强 D.糖原分解
基础心理学是研究()。 (A)正常成人心理现象的心理学基础学科 (B
根据《环境影响评价技术导则—大气环境》,大气环境影响评价中,经过对建设项目的初步
(2015年真题)关于招标方式的说法,正确的是( )。A.公开招标是招标人以招
加气混凝土砌块墙如无切实有效措施,不得使用于()。A.建筑物室内地面标高以
最新回复
(
0
)