题干

回忆一下你所做过的以下实验,其中相关操作正确的是(    )

序号

实验名称

部分操作

A

观察青霉

用解剖针挑取少许菌丝,放在载玻片上,直接用显微镜观察

B

观察酵母菌

转动转换器换成高倍物镜,再转动粗准焦螺旋使物像清晰

C

观察人口腔上皮细胞

将牙签附有碎屑的一端放在载玻片上的生理盐水中轻涂几下

D

观察小鱼尾鳍内血液的流动

用高倍物镜观察小鱼尾鳍血管内血液的流动情况

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:2018-11-29 06:28:54

答案(点此获取答案解析)

C

同类题1

阅读理解

    Rick Garcia is going to play outside with his friends. He is taking out his reliever inhaler (缓解物吸入器) and taking two puffs (吸). Five minutes later, he's on the field with his friends, running after a soccer ball. Rick has asthma (哮喘), but he knows how to control it.

    Asthma is a lung disease. A person with asthma may cough or suffer from shortness of breath. Asthma can begin at any age. Childhood asthma, often beginning when a child is younger than 10 years old, is one of the most common childhood diseases. Doctors report that the number of young people with asthma is increasing. It is the number one cause of absence from school. If parents have asthma, their children are more likely to develop the disease. Children in homes where an adult smokes are more at risk.

    It is important to find out the triggers for asthma. As we know, dust, pollen, or animals often make people suffer from asthma. Once a child learns the triggers, he can help prevent future attacks. About half of all children outgrow asthma and then asthma attacks stop when they are teenagers. However, many people live with the disease into adulthood.

    Children often take control drugs once or twice a day to help prevent asthma attacks, if a child begins to have an asthma attack, a quick-relief drug is also necessary. This is often an inhaler. School-aged children usually carry their inhalers with them. This medication works quickly and children begin to breathe more easily in a few minutes. If a child has a serious asthma attack, he may need full-time care at a hospital or a doctor's office.