问题 单项选择题

如图分别表示对几种生物体内正在进行分裂的细胞进行观察的结果,有关假设推论正确的是()

A.若图甲为有丝分裂过程中的某阶段,则下一时期细胞中央将出现赤道板

B.若图乙表示有丝分裂过程中的某阶段,则染色体着丝点分裂可发生在这一阶段

C.若图乙表示减数分裂过程中的某阶段,则同源染色体的分离可发生在这一阶段

D.若图丙表示雄果蝇精巢内的几种细胞,则c组细胞中可能出现联会和四分体

答案

参考答案:C

解析:

图甲表示植物细胞有丝分裂后期,下一时期在细胞赤道板的位置将出现细胞板,A错误。若图乙表示有丝分裂过程中的某阶段,该阶段每条染色体有两条染色单体,含2个DNA分子;可能处于前期和中期,不可能发生着丝点分裂,B错误。若图乙表示减数分裂过程中的某阶段,含有染色单体的时期为减数第一次分裂和减数第二次分裂前期和中期;同源染色体分离发生在减数第一次分裂后期,属于上述阶段内,C正确。若图丙表示雄果蝇精巢内的几种细胞,c组染色体组加倍,发生有丝分裂,没有联会和四分体的形成,D错误。

考点:本题考查细胞分裂过程DNA含量与染色体数目变化规律,意在考查考生识图能力和理解所学知识的要点,把握知识间的内在联系,形成知识网络结构的能力。

阅读理解

阅读理解

     Do you remember piling up building blocks (积木) when you were younger?In order for a great

structure to be created,you needed skill,patience,hard work,and the right blocks.To build a healthy and

happy life,you need skill,patience,hard work,and the right blocks.In life,though,these blocks,or tools,are

called life skills.

     No one wants to feel frustrated.No one wants to feel sick.No one wants to fight all the time with friends

or family.When these issues come up,though,life skills can help you deal with and improve the situation.

     Do you remember the six components of health?They are physical,emotional,social,mental,spiritual,and

environmental.Life skills can help improve these areas individually or,sometimes,together.It just takes

practice.So what are the life skills?

     First of all,an individual should assess his health.Doing this helps the person decide on his current state

of wellbeing and pick the actions and behaviors that will improve his health.

     Second,a person should try to communicate effectively.When a person can clearly state his feelings and

listen effectively as well,relationships with others can improve.

     Third,an individual should practice wellness.This means the person is trying to choose nutritious meals,

avoid unhealthy behaviors,and get enough sleep.

     Fourth,________.Each person will experience difficult situations.Each person experiences anger or

depression at some point in his life.To build a healthy life,though,a person works through the situation.

    Fifth,a person needs to be a wise consumer.A consumer buys products.A wise consumer makes healthy

decisions when buying products and services.

1.The author talks about piling up building blocks in the first paragraph to________.

A.show it is a difficult task

B.compare it with building a healthy life

C.explain how to create a great structure

D.tell readers the six components of health

2.The underlined word "wellness" in the passage most probably means "________".

A.having a lot of money

B.the state of being healthy

C.being content with what one has

D.being not easily upset or excited

3.Which of the following sentences can be used to fill in the blank?

A.a person should learn from failure

B.a person should work hard all his life

C.a person may have troubles every now and then

D.an individual must try to deal with troubles effectively

单项选择题