According to Prof．Mark Bellis，__________． 查看材料
A. e-cigarettes contain something addictive which has a longstanding effect on kids
B. e-cigarettes may be harmful to the lungs and immune system
C. the use of e-cigarettes penetrates into youth culture as rapidly as other drug uses
D. e-cigarettes make teenagers who have never smoked before start smoking
What do we learn from the survey made among students in the North West of England？
A. E-cigarettes are now widely available and heavily promoted．
B. The number of adult cigarette smokers is dropping at present．
C. Teenagers are very knowledgeable about alcohol and tobacco use．
D. E-cigarette access is linked to excessive drinking and violence after it．
α螺旋、β折叠和π螺旋()。
A. 一级结构
B. 二级结构
C. 三级结构
D. 四级结构
E. 变性
多肽链盘曲折叠形成的空间结构()。
A. 一级结构
B. 二级结构
C. 三级结构
D. 四级结构
E. 变性
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