题干

如图图中的甲图表示植物的淀粉酶与人的淀粉酶活性受pH影响的情况,乙图表示3种脱氢酶(A,B,C)的活性受温度影响的情况.下列叙述正确的是(  )

①pH=5时,植物淀粉酶的活性最高

②人的淀粉酶活性随PH值的降低而渐渐升高

③乙图中,适宜温度范围最广的酶是B

④乙图中,无法确认C酶活性的最适温度

A:①②

B:①③

C:①④

D:②

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答案(点此获取答案解析)

C

同类题3

Mobile phones and the Internet have improved our life in many ways. However, along with improvements, they also brought a number of worrying problems.
Many car accidents are caused by mobile phones. You can use many new mobile phones to get on the Internet .This can be very convenient, but some drivers get on the Internet while driving. Driving needs all our attention. By looking at their mobile phones and not at the road, these insensitive(不专注的) drivers are a danger to us all.
Many of the dangers of the Internet are well known. Children who visit websites without their parents' permission sometimes talk to older people they don't know and put themselves in great danger. People with blogs(博客) sometimes post(张贴) embarrassing photographs of people they don't know on their websites without permission. There are also people who use the Internet to get personal information that we do not want them to have.
Mobile Phones and Internet Safety Tips
l If you need to use a mobile phone when you drive, use a "hand –free" phone.
l In difficult driving situation such as rain or snow, don't use your phone at all.
l Do not make very important phone calls while driving. They take your attention off the road.
l Tell your children not to talk with anyone they do not know on the Internet.
l In an embarrassing situation, pay attention to people around you. People will be shy about taking your picture if they know you're paying attention.
l Refuse to give out any personal information on the Internet.