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问题 单项选择题

蛇毒、尸毒等毒物因素属于（）。

A.生物性致病因素

B.物理性致病因素

C.化学性致病因素

D.机械性致病因素

E.营养性致病因素

答案

参考答案：C

解析：疾病发生的原因包括外因和内因。疾病发生的内因包括生物性因素，如各种病原微生物和寄生虫；化学性因素，包括强酸、碱、有机毒物、生物性毒物，如蛇毒、尸毒等；物理性因素，包括高温、低温、电流，机械性因素；营养性因素，包括营养缺乏和营养过剩等。因此，蛇毒、尸毒等毒物因素属于化学性致病因素。

单项选择题

常用水泥在正常环境中存放三个月，一般强度降低（）

A.15％～20％

B.10％～20％

C.10％～15％

D.10％以下
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单项选择题

Students at a certain university have complained that some of their professors do not provide copies of their lecture notes at every class. The student body president has argued that, in order to further the educational purposes of the university, all professors should be required to post their lecture notes online.
Which of the following, if true, most weakens the students’ argument that the professors should be required to post their lecture notes online ？（）

A. At the most popular classes, there are often insufficient quantities of lecture note copies to accommodate all of the students.

B. Students have acknowledged that if the lecture notes are posted online, they will be less likely to go to class.

C. Professors complain that the university does not provide sufficient copying funds, so that professors often have to pay for copies of lecture notes out of their own pockets.

D. Over 80 percent of students have access to the Internet in their dorm rooms, and all students have 24-hour access to the Internet at the computer lab.

E. The university has publicly stated that one of the educational goals of the university is to help all students gain competency with the Internet.
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