题干

下列关于生物实验活动的操作步骤与其相应的目的,正确的是(  )


实验活动

操作步骤

操作目的

A

练习使用显微镜

转动转换器

调节光线强弱

B

验证绿叶在光下制造淀粉

把叶片放入酒精中直接加热

使叶片脱色

C

观察叶片结构

用稀碘液染色

把细胞核染成深色

D

制作人口腔上皮细胞临时装片

洁净载玻片上滴加生理盐水

保持细胞原有形态

A:A

B:B

C:C

D:D

上一题 下一题 0.0难度 选择题 更新时间:2014-01-10 09:19:10

答案(点此获取答案解析)

D

同类题2

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Doctors SayMost Heart Disease Preventable

               Heart disease is the number one killer,worldwide, of men and women over the age of 60. But people of all ages die ofheart attacks each year. And while death rates have declined in the U.S. and many western European countries, they are on the risein the developing world.____ .

          No one would have guessed that Barbara Tengwould have a heart attack. She was not overweight. She did not smoke orexercise. “In 2004,the week after Iturned 49 ,when I was on abusiness trip in Chicago,Ihad a major heart attack,”shesaid.____. She now exercisesdaily, and monitors her heart health.

 Dr. Patrice Nickens, who is with the NationalHeart, Lung and Blood Institute, thinks that heart disease is 82 percentpreventable. “____,” she said.“Men are also facing the same problem, and thekey to staying healthy is knowing your numbers.”

 “Your weight, your blood cholesterol, bloodsugar and your blood pressure are important numbers that can help you takeaction and reduce your risk,”she said.

____.

    “And the steps to take are simple:don't smoke, maintain a healthy weight, exercise, know yournumbers and talk to your physician and control these risks,” she said.

 African­Americans are at higher­than­averagerisk for heart disease and stroke;peopledon't even know they have it, which increases the risk. Medstar WashingtonHospital Center is trying to reach this population.____. For example, helping the peoplemonitor their blood pressure. If people realize they are at risk for heartdisease, they'll make lifestyle changes: lose weight, exercise, eat the rightfoods and keep in touch with a doctor.

a.A healthy lifestyle can prevent heart disease

b.So we must cure heart disease

c.It is the leading cause of death for women

d.With the right training, they can play an important role incommunity health

e.And that changed her life

f.Lack of exercise causes heart attacks

g.Yet most heart disease is preventable