问题 选择题

下列说法不正确的是(  )

A.人类起源于森林古猿,且生命起源于原始的海洋

B.生物进化的大致历程是:由简单到复杂、由高等到低等、由水生到陆生

C.在研究生物的进化过程中,化石是非常重要的证据

D.在生物的进化过程中,适应环境的生物就生存下来,不适应环境的生物就被淘汰

答案

A、人类起源于森林古猿,人类学家将是否直立行走作为人猿分界的一个重要标准;化学起源学说认为:原始大气在高温、紫外线以及雷电等自然条件的长期作用下,形成了许多简单的有机物,随着地球温度的逐渐降低,原始大气中的水蒸气凝结成雨降落到地面上,这些有机物随着雨水进入湖泊和河流,最终汇集到原始的海洋中.原始的海洋就像一盆稀薄的热汤,其中所含的有机物,不断的相互作用,经过及其漫长的岁月,逐渐形成了原始生命,因此原始海洋是原始生命的摇篮.

B、由生物起源的化学进化论可以发现在原始地球的条件下,无机物可以转变为有机物,有机物可以发展为生物大分子和多分子体系,直到最后出现原始的生命体.生物通过对不同类群生物的形态结构、生殖方式以及生活环境进行比较、分析,可以发现生物进化遵循由简单到复杂,由低等到高等,由水生到陆生的规律.

C、生物学家通过对不同类群生物的形态结构、生殖方式以及生活环境进行比较、分析,可以发现生物进化遵循由简单到复杂,由低等到高等,由水生到陆生的规律.而形成与不同地层里的化石也印证了这一点越古老的地层里的生物化石越简单、越低等、水生的越多;越新近形成的地层里的生物化石越复杂、越高等、陆生的越多.所以在研究生物的进化过程中,化石是非常重要的证据

D、自然界中生物进化的原因有两方面:内因是遗传变异,外因是自然选择.自然选择包括过度繁殖、生存斗争、适者生存与不适者被淘汰三个过程.变异是不定方向的,是否有利要看这种变异是否适应环境,为生物进化提供原始的材料.然后过度繁殖为自然选择提供了动力,以生存斗争为手段,达到适者生存与不适者被淘汰的结果.

故选:B

阅读理解

Mary picked up a pencil and a piece of paper,saying,“Now,you want to earn money for the autumn camping trip,right?” Tom,her brother,nodded.He wasn’t able to go last year because he hadn’t earned enough money during the summer.This year he came up with a plan.

He made a necklace for his mother that everyone admired.They were surprised to learn that Tom had made it for her.Why not make more necklaces and sell them?

“OK,” said Mary,“The first thing you need to do is to figure out(计算)how much you have now.’’

“I have $20.00 in the bank,and $7.25 in my room,” explained Tom.

“That gives you a total of $27.25,” said Mary,“That is called your capital.The next thing you need to know is how much it will cost you to make each necklace.”

“Well,the pet shop will give me all the feathers the birds lose.I'll have to buy the beads(小珠子)and string,” said Tom.

Mary wrote on the piece of paper:

CAPITAL      $27.25

EXPENSES     Feathers                       no cost

String for 10 necklaces        $  2.50

Beads for 10 necklaces   +    $ 15.00

Total                        $ 17.50

“How much do you think you can sell such a necklace for?” asked Mary.

“Hmm,” Tom looked thoughtful and said,“There's a shop in town that sells almost the same kind of necklace for $ 7.50.If I charge(要价)$ 6.00,people will think that's a bargain.”

“OK.If you sell each necklace for $ 6.00,you'll make a good profit(利润)on each then,” said Mary.

“Hurray!” Tom cried,“If I sell 20 necklaces,I'll have enough from the profit for the camping trip and $10.00 left over.”

小题1:The underlined word "bargain" in this story means “________”.

A.something sold cheap

B.something sold expensive

C.something made at home

D.something made by children小题2:How much would Tom have to spend on the camping trip?

A.$ 47.45.

B.$ 75.

C.$ 85.

D.$102.25.小题3:What's the best title for this story?

A.How to Make Necklaces

B.How to Sell Necklaces

C.How to Make a Plan

D.How to Earn Money for a Trip

单项选择题