题干

实验小组为探究“乳酸菌无氧呼吸是否有气体产生”,设计如下图所示的两个实验装置,两装置均置于25℃的恒温水浴中,下列说法正确的是

A:乙装置的气球中应注入甲装置等量的乳酸菌培养液并通入O2

B:实验中使用的培养液需煮沸冷却处理,目的是控制自变量

C:25℃恒温的目的只是控制环境温度变化对实验的影响

D:预期最可能的实验结果是两个烧杯液面基本无变化

上一题 下一题 0.0难度 选择题 更新时间:2019-01-16 12:01:17

答案(点此获取答案解析)

D

同类题4

阅读理解

    Are you scared about moving up to senior high school?It can be a new experience,but you shouldn't worry.We've put together a guide on how to survive the first week.

    You're not alone

    Remember everybody else in your year is in the same boat.They may not realize it,but they're just as nervous as you are.Moving to senior high is an opportunity,not a problem.Things are different and all you need to do is be polite and learn the new rules.

    Teachers are ready to help!

    If you're unsure what to do or are worried about anything then you had better ask for help.Teachers are probably the best people to turn to as they're experienced in helping new students.Some senior high schools also have a “friends system”.If your school has this,then you will be paired with an older student.They will look out for you and help you if you have any problems or questions.

    All change

    There are lots of differences between junior high school and senior high school.You'll have a homework diary or a student planner.You will have your lessons with different teachers in different rooms.You will have homework for different subjects on different days,so make sure you get organized.Make sure you have a copy of your school timetable written down so you know which rooms your classes are in and on which days you will have your different subjects.

Other points

    If you've got an older brother or sister at the school then ask them for advice.

    Be yourself! It sounds simple,but people will know you much better if you just act naturally.

    Having early nights makes a difference and you'll find it easier to get up in the morning!