题目

某生物兴趣小组的同学在探究“水分进入植物体内的途径”后得出了如下结论，你认为不正确的是（ ） A．根吸水的主要部位是根尖的成熟区           B．根、茎、叶的导管是连通的 C．筛管是运输水和无机盐的主要通道    D．水和无机盐的运输方向是“根→茎→叶” 答案：C 【分析】 本题考查探究茎对水分和无机盐的运输。茎是主要的输导器官，其中含有输导组织--导管和筛管。 【详解】 植物主要靠根吸水，吸水的主要部位是根尖的成熟区，根尖从下至上分别为根冠、分生区、伸长区、成熟区。成熟区有大量的根毛，大大增加了吸水的表面积，提高了吸水的效率。成熟Sleep is a basic human need, as basic as the need for oxygen. Getting a good night’s sleep is not only directly related to how we feel the next day, but to our long-term health as well. However, many of us suffer from insomnia (失眠). Even more odf us report at least one night of restless sleep per week. This is a serious problem.Well, how can we make sure that we rest well and stay healthy? Here are some suggestions.If you can’t sleep in the middle of the night, don’t get up. The bright light will affect your body clock and worsen your insomnia. Stay in bed!Avoid short sleep during the day, except for a brief ten to fifteen-minute sleep between 2:00 and 4:00 P.M.Limit your time in bed to the average number of hours you ‘ve actually slept per night last week. Don’t try to make up for lost sleep. It can’t be done.Get regular exercise each day, but finish at least six hours before bedtime. Exercising in the evening can help keep you awake.Take a hot bath for thirty minutes within two hours of bedtime. The bath will warm you, relax you, and make you feel sleepy.Keep our bedroom dark, quiet, and well ventilated (通风).Keep a regular schedule seven days a week. Avoid sleeping late on weekends. Although it may feel good while you’re doing it, sleeping late on weekend can lead to insomnia during the week.Don’t drink alcohol (酒精). Although, having a drink before bed makes you sleep, alcohol loses its effects after a while. The secondary effects of alcohol can wake you up during the second half of your night’s sleep.Keep the face of the clock in your bedroom turned away, and don’t find out what time it is when you awaken in the night.1.The first paragraph serves as a(n) __________.A. comment B. argumentC. explanation D. introduction2.Which of the following is NOT advised for a good night’s sleep?A. Don’t exercise six hours before sleeping.B. Preventing the wind from blowing into your room.C. Staying in bed after failing to sleep.D. Don’t drink alcohol before sleeping.3.To sleep well, you need to __________.A. sleep during the day sometimesB. get up late on weekendsC. avoid looking at your clockD. have a bath in the morning4. The text mainly about__________ .A. some effects of bad night’s sleepB. some advantages of having a good sleepC. some reasons for insomniaD. some keys to a better night’s sleep