题干

某生物的体细胞染色体数为2n。该生物减数第二次分裂与有丝分裂相同之处是(   )

A:分裂开始前,都进行染色体的复制

20070123

B:分裂开始时,每个细胞中的染色体数都是2n

C:分裂过程中,多条染色体的着丝点都分裂成为两个

D:分裂结束后,每个子细胞的染色体数都是

上一题 下一题 0.0难度 选择题 更新时间:2018-03-14 04:02:51

答案(点此获取答案解析)

C

同类题2

任务型阅读

How to Manage Your Phone's Data Use

    Smart phones give you access to a wealth of information and media, but most networks put a limit on the amount of data you can use each month. A typical phone contract includes a data allowance of between 500MB and 10GB per month. ____ You see, your usage can mount up surprisingly quickly – watching a film on the phone is about 700MB in SD, an hour of streaming TV is around 500MB or 60-140MB for the same of radio, chatting on Skype for an hour is around 40MB. ____

    If possible, wait until you can connect to free Wi-Fi before using your phone's data features.

    When you are on the road, use your car's GPS, not your phone, to find the way. ____ But maps are preloaded in a GPS, making this free to use.

    ____ Many of these are funded by ads that pop up on your screen. Every ad has to download through your network, using up your data allowance.

    If you regularly need to use a lot of data on your phone, consider a data-compressing(压缩) app, such as Onavo(www.onavo.com). ____ So you use less of your monthly allowance. You may have to subscribe to such compression services, so you'll need to weigh up whether it's worth the cost.

A. The more data, the higher the monthly cost.

B. Remember to use free Wi-Fi anywhere you go.

C. Try these tips to better manage your data use.

D. It compresses data before it is fed to your phone.

E. But you might end up paying more than expected.

F. The phone has to download map data as you move.

G. Be careful of how many “free” games you play on the phone.