首页
登录
职称英语
[originaltext] A new study suggests climate conditions in the Sahara Desert
[originaltext] A new study suggests climate conditions in the Sahara Desert
游客
2023-08-04
51
管理
问题
A new study suggests climate conditions in the Sahara Desert have changed from wet to dry about every 20000 years. The study was carried out by scientists at America’s Massachusetts Institute of Technology, or MIT. Findings were published in the journal Science Advances. The research was partly funded by the National Science Foundation.
The Sahara Desert is known as one of the hottest, driest and most desolate areas in the world. But previous evidence has suggested the Sahara did not always experience such extreme heat and dry conditions. The evidence included material collected from fossils and rock paintings from the area. The evidence showed that at times, the Sahara changed to a very wet climate. This permitted plants and animals to develop and grow and led to the creation of human settlements. Now, researchers have discovered more evidence of this changing climate. The scientists examined dust gathered from the coast of West Africa over the past 240000 years. The research showed that during that period, the Sahara’s climate kept changing between wet and dry about every 20000 years.
David McGee is an associate professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences. He helped lead the study. McGee said the new evidence supports the idea that the area’s climate repeatedly kept changing over the years. " Our results suggest the story of North African climate is dominantly this 20000-year beat, going back and forth between a green and dry Sahara, " he said. McGee and other researchers reported these back and forth climate changes were mainly driven by changes in the Earth’s axis as the planet orbits the sun. This process affects the amount of sunlight between seasons. The research suggests that every 20000 years, the Earth receives more intense summer sunlight. When the Earth’s axis changes again, the amount of sunlight is reduced. This season change happened continuously every 20000 years, the study found. The other part of the season produced monsoon conditions, resulting in a wetter, greener, plant-rich environment. When the rainy activity weakens, the climate becomes hot and dry, like the Sahara remains today. The scientists based their research on dust samples collected from ocean sediment. McGee says he thinks the latest research can be valuable in studying the Sahara’s history as it relates to human settlement. "What times could have been good for humans to settle the Sahara Desert and cross it to disperse out of Africa, versus times that would be inhospitable like today, " he said.
Questions 19 to 22 are based on the recording you have just heard.
19. What does the new MIT research find about the Sahara Desert?
20. What was the previous evidence showing that the Sahara did not always experience extre conditions?
21. What caused the climate changes in the Sahara Desert?
22. Why does McGee believe that the latest research is valuable?
选项
A、Materials collected from plants and animals in the Desert.
B、Materials collected from fossils and rock paintings in the Desert.
C、Dust gathered from human settlements along the coast of West Africa.
D、Dust gathered from the coast of West Africa over the past 240000 years.
答案
B
解析
原文中提到,先前的证据表明,撒哈拉沙漠并不总是经历极端的高温和干燥的条件。这一证据包括从该地区的化石和岩石画中收集到的材料。因此答案为B。
转载请注明原文地址:https://tihaiku.com/zcyy/2897085.html
相关试题推荐
[originaltext](23)WiththeInternetrevolutionusheringinnewmodesofco
[originaltext](23)WiththeInternetrevolutionusheringinnewmodesofco
[originaltext]Hereisaquestionforyou.Thecustomerisalwaysright.Rig
[originaltext]Hereisaquestionforyou.Thecustomerisalwaysright.Rig
[originaltext]Moderator:Hello,ladiesandgentlemen.Itgivesmegreat
[originaltext]Moderator:Hello,ladiesandgentlemen.Itgivesmegreat
[originaltext]Moderator:Hello,ladiesandgentlemen.Itgivesmegreat
[originaltext]MedicalexpertssaymostAmericansdonotgetenoughsleep.T
[originaltext]TheWorldHealthOrganizationsays57nationsinSouthernAfr
[originaltext]W:WhatdoyouthinkofTV?Ithinkitisafalsegod,adang
随机试题
Insuchachanging,complexsocietyformerlysimplesolutionstoinformatio
不是大黄使用注意的是()A.妇女月经期忌用 B.妇女哺乳期忌用 C.冷
中、小比例尺地图缩编中,用图形符号表示居民地时,符合制图要求的居民地选取方法有(
新生儿窒息时,医护人员采取首要的复苏步骤是A.清理呼吸道 B.建立呼吸 C.
共用题干 某零售商计划从四个备选地区中选择一个合适的地区开设一家零售商店,每个
根据企业战略管理的要求和绩效管理组成要素之间的关系,可以按照以下步骤进行绩效管理
目前,我国对五种运输方式实行管理的政府部门包括( )。A.铁道部 B.交通运输
根据《中华人民共和国河道管理条例》,城镇建设和发展不得占用河道滩地。沿河城镇在编
特大型停车场出人口不得少于三个,并应设置专用人行出入口,且两个机动车出入口之间
患者,男性,64岁,头晕、心悸4~5年,心尖搏动向左下移位,呈抬举性搏动,于胸骨
最新回复
(
0
)