题干

下列属于变态发育的是(  )

①蝌蚪发育成青蛙  ②“毛毛虫”发育成蝴蝶  ③蚕幼虫发育成蚕蛾  ④雏鸡发育成大公鸡.

A:①②③

B:①②④

C:②③④

D:①③④

上一题 下一题 0.0难度 选择题 更新时间:2016-04-27 05:27:04

答案(点此获取答案解析)

A

同类题3

科技的发展是大国崛起的重要原因。崛起后的大国在谋求各自利益和新发展的过程中又影响了世界格局的发展演变。阅读下列材料,回答问题。
材料一  18世纪中期到19世纪中期,蒸汽机引起了欧洲生产的革命,……英国引领了这一历史发展的潮流,取得了技冠群雄、傲视全球的辉煌成果。
(1)材料一中“蒸汽机引起的欧洲生产的革命”对人类历史的发展产生了什么重要的影响?英国能引领这一历史发展潮流一个重要的原因是它率先完成了资产阶级革命,它完成资产阶级革命后确立了怎样的政治体制?
材料二  在十九世纪后期,落后于英国和法国技术的美国技术,突然获得了大发展,并以电灯、打字机、电话以及三样革命性进展——电、汽车和飞机——改变了世界。
——沃尔特·拉斐伯《美国世纪》
(2)依据材料二并结合所学知识,指出美国“革命性进展”得益于哪一次技术革命?这次技术革命把美国带人了什么时代?
材料三 所有的大国都试图建立符合自己利益的世界秩序,所以它们总是为世界秩序出谋划策。实际上,那些正在崛起的国家想要打破这种秩序,因为它们试图取代以前的大国。
(3)一战后,英法美等资本主义国家先后召开了哪两次会议建立了符合自己利益的世界秩序?二战后形成了两极格局,请写出这一格局形成的标志性事件。
材料四   美国、西欧、日本在不同时期世界工业生产中比重的变化图

(4)材料四图示反映出西欧、日本二战后工业生产在世界上所占的比重,呈现怎样的变化趋势?请写出西欧、日本为实现这一变化采取的共同措施。
材料五 当今世界,除美国之外,欧盟、日本、俄罗斯、中国等多种政治力量不断发展壮大。他们在国际事务中发挥着越来越大的作用。
(5)材料五反映出当今世界政治格局的发展趋势是什么?

同类题4

阅读理解

Bicycle Safety

    Operation Always ride your bike in a safe, controlled manner on campus(校园). Obey rules and regulations. Watch out for walkers and other bicyclists, and always use your lights in dark conditions.

    Theft Prevention Always securely lock your bicycle to a bicycle rack — even if you are only away for a minute. Register your bike with the University Department of Public Safety. It's fast, easy, and free. Registration permanently records your serial number, which is useful in the possible recovery of the bike stolen.

Equipment

    Brakes Make sure that they are in good working order and     adjusted properly.

    Helmet A necessity, make sure your helmet meets current safety standards and fits properly.

    Lights Always have a front headlight — visible at least 500 feet in front of the bike. A taillight is a good idea.

Rules of the Road

    Riding on Campus As a bicycle rider, you have a responsibility to ride only on streets and posted bicycle paths. Riding on sidewalks or other walkways can lead to a fine. The speed limit for bicycles on campus is 15 mph, unless otherwise posted. Always give the right of way to walkers. If you are involved in an accident, you are required to offer appropriate aid, call the Department of Public Safety and remain at the scene until the officer lets you go.

    Bicycle Parking Only park in areas reserved for bikes. Trees, handrails, hallways, and sign posts are not for bicycle parking, and parking in such spots can result in a fine.

If Things Go Wrong

    If you break the rules, you will be fined. Besides violating rules while riding bicycles on campus, you could be fined for:

No bicycle registration  ………………..……………….…… $25

Bicycle parking banned   …………..…………………….……$30

Blocking path with bicycle   …………………………….……$40

Violation of bicycle equipment requirement  ……………....…$35

根据短文内容,选择最佳答案,并将选定答案的字母标号填在题前括号内。