搜题请搜索小程序“爱下问搜题”
问题 单项选择题 共用题干题

患者，女性，10岁，替牙牙合。磨牙近中关系。前牙反牙合4mm，下颌前突。下颌体稍长，下颌位置前移，上颌前颌骨区发育稍差。

如患者伴有单侧后牙反牙合治疗方法是（）

A.调牙合

B.单侧牙合垫式活动矫治器

C.改正单侧咀嚼习惯

D.治疗后牙区龋齿

E.以上都可以

答案

参考答案：E

单项选择题 A1型题

1型糖尿病的病因不包括（）

A.遗传因素

B.饮食因素

C.病毒感染

D.化学物质

E.缺乏体力活动
查看答案
单项选择题

Lichens may grow on the bark of a tree in a steaming tropical rain forest, on the bricks of big city buildings, on rocks in hot springs, on wind-swept mountaintops, and in the driest desserts. In the arctic, they provide the principal food for caribou, and they are one of the few plants that grow in Antarctica. They are pioneers, appearing in barren rocky areas and starting the formation of soil in which mosses, then ferns, and then other plants can take root.
Lichens are a partnership of two plants — fungi and algae. The lichen body is made up of a network of fungal strands. In the upper layers of these grow groups of algae. The two organisms live together to the benefit of both, a relationship known as symbiosis. The fungi provide support, absorb water, and shelter the tender algae from direct sunlight. The algae carry on photosynthesis and provide the fungi with food. The algae can live independently and are recognizable as a species that grows alone. The fungi, on the other hand, cannot live apart from their partners. They can be placed in known classes of fungi but are unlike any species that lives independently.
So definite are the form, color, and characteristics of these double organisms that for hundreds of years, they were classified as one. More than 15,000 "species" were named. If these organisms are classified as separate species, it is difficult to fit them into the existing system of classification. But if they are classified separately, these species of fungi seem rather strange. Lichens are a splendid example of the difficulties faced by taxonomists in classifying species.

What does the author imply about lichens in Paragraph 1

A．They require a lot of moisture to live.
B．They primarily live in cold places.
C．They can live anywhere except around people.
D．They have adapted to a wide variety of environments.
查看答案