切开熟透的西瓜时，有浅红色的汁液流出来，这些汁液主要来自[]A．细胞壁B．细胞膜C．细胞核D．液泡-八年级生物

更多内容推荐

• 阅读理解。 The best way of learning a language is using it. The best way of learning English is talking i
• 阅读理解。 During the day we work and play and at night we sleep. Our bodies rest while we sleep. In the
• 阅读理解。 There is a handsome boy. He has golden hair and a pair of big blue eyes. But he looks very sad
• 完形填空。Many people today like reading stories about UFOs. Many people in different countries are1 UFOs
• 阅读理解。 Do you believe there are aliens (外星人) ? Well, make a phone call and you will know. A group of
• 丽丽穿的白裤子被鲜菠菜汁染上绿色，能将这一污迹除去的最佳材料是[]A．普通洗衣粉B．酒精C．沸水D．肥皂水-八年级生物
• 完形填空。 On the first day of school, the new teacher had a look at the name list of students. How pleas
• 完形填空 Now satellites are1 to forecast (预报) the weather. They are in space, and they can2 any part of
• 请指出植物细胞结构简图中部分结构名称标号1是______，标号2是______，标号3是______，标号5是______．-生物
• 恩吉尔曼把载有水绵和好氧性细菌的临时装片放在无空气的黑暗环境里，用极细的光束照射水绵。显微观察发现，好氧性细菌只集中在叶绿体被光束照射到的部位附近；如将上述装片完-七年级生物
• 福桔的果肉酸甜可口，其酸甜的物质主要贮存在[]A．细胞壁B．液泡C．细胞核D．细胞膜-八年级生物
• 阅读理解。 Antifreeze is a liquid (液体) that is added to water to keep it from freezing. When water freeze
• 阅读理解。 The dog of the future (未来) is here, and you don't need to feed it or walk it behind it. T
• 根据短文内容及所给首字母填写所缺单词 Many people find exams a frightening experience.Sitting down for an exam when eve
• 完形填空。 I am a student in Grade Three. I began to learn English the year before last. English isn'
• 阅读理解。 A prairie is a type of grassland. Prairies are made up of a complete interdependent ecosystem.
• 西瓜之所以甘甜可口，主要是因为西瓜的下列哪项含有大量的糖分[]A．细胞壁B．细胞膜C．细胞液D．细胞核-七年级生物
• 阅读理解 Many parents make their children do chores around the house. For some families, teaching childr
• 完形填空 The Japanese Macaca monkey has been studied in the wild for over 50 years. In 1952 ,on one smal
• 根据短文大意选择方框内的单词并用其正确形式填空，使补全后的短文意思通顺，语法正确，结构完整。walk, way, without, prevent, easy Trees are useful in
• 阅读理解 Scientists think that a weather pattern( 形式)calledE1 Nino( 厄尔尼诺现象)caused the drought( 干旱)in Au
• 要判断某一球形的多细胞生物是植物还是动物，下列哪种办法是可行的（）A．在显微镜下观察它的细胞是否有细胞壁B．给它提供适宜的环境，看它是否发生细胞分裂C．刺激它，看它是否能-生物
• 阅读理解。 New rules and behavior standards (行为规范) for middle school students came out in March. Middle s
• 植物叶肉细胞内有两种“能量转换器”。下列能将光能转变成化学能的细胞结构是[]A．叶绿体B．细胞核C．线粒体D．细胞膜-七年级生物
• 下列植物细胞结构中，对细胞有保护和支持作用的是[]A．细胞膜B．细胞壁C．细胞核D．液泡-七年级生物
• 阅读理解。 Does it feel like you and your parents just can't see eye to eye? Are you always fighting
• 切洋葱时常会引起流泪，原因是洋葱组织细胞中含有对眼睛有刺激的物质，这些物质主要存在于[]A．细胞壁B．细胞膜C．细胞核D．液泡-七年级生物
• You may feel interested in students in other countries.Do they have so much homework? What do they
• 阅读下面的短文，并用方框中的词语填空。finally relish tomato then putHere's a recipe for a great turkey sandwich! F
• 阅读短文，根据其内容回答问题。 The idea of daylight (日光) saving time started with an American named Benjamin Frankl
• 下列生物的细胞中具有液泡的是[]A．人类与水稻B．狗与小麦C．小麦与水稻D．猪与牛-七年级生物
• 阅读理解。 Robots seem very new to most people. But theyhave a long history. The first one was made by a
• 阅读理解。 The rockets take astronauts and man-made satellites into space. The satellites are used for co
• 阅读理解。 Girls wore grey skirts and white shirts, boys wore grey trousers, and everyone wore the school
• 阅读理解 Germs(细菌 ) are everywhere. You can't see them, but they are on your desk,on your computer,
• 下图是植物细胞结构模式图，据图回答问题．（1）动物细胞没有的、植物细胞特有的结构并是绿色植物进行光合作用的是场所是______A、标号4B、标号3C、标号2D、标号5（2）起保护和支-生物
• Reading comprehension. Each year, many Chinese people go abroad because of all kinds of reasons. The
• 通过实验观察，黄瓜表层果肉细胞和人的口腔上皮细胞都有的结构是①细胞壁②细胞膜③叶绿体④线粒体⑤细胞核⑥液泡⑦细胞质[]A．①③④⑦B．②③⑥⑦C．②④⑤⑦D．①④⑥⑦-八年级生物
• 下图是植物细胞模式图。请据图回答：（1）图中①表示细胞壁，起__和___细胞的作用。（2）图中②表示___。（3）如果该图表示叶肉细胞，细胞内含有的能量转换器是___和___。-八年级生物
• 阅读短文，根据短文内容，从短文后的五个选项中，选出能填入空白处的最佳选项。选项中有一项为多余选项。 Do you have enongh time to do all the things you h
• 在显微镜下观察一个成熟的植物细胞，你会发现细胞核不在细胞的中央，而是位于细胞的一侧，造成这种现象的原因是[]A．细胞质的流动B．细胞的分裂C．细胞核的活动D．液泡的膨胀-七年级生物
• 阅读理解。 American schools begin in September after a long summer holiday. There are two terms in a scho
• 仔细识别图，然后回答下列问题．（1）此细胞是______细胞（填“动物”或“植物”），它与另一类生物细胞共有的结构是______（用文字叙述）．（2）能控制物质进出的是[2]______．（3）[1]
• 完形填空 In some science fiction movies,the robots(机器人) are just like humans. They help with the housewo
• 阅读理解。 Guinea Pigs (荷兰猪) are friendly animals that enjoy being held and seldom bite. They come from S
• 春雪过后，有些植物会被冻死。植物被冻死的主要原因是[]A．雪天光照不足，植物光合作用停止B．地面结冰，植物无法吸水C．细胞液结冰，体积增大，导致细胞破裂，引起细胞死亡D．低-八年级生物
• 完形填空。 How much do you know about storms? Storm is a kind of very bad1 with strong wind and rain. Sto
• 阅读理解。 There have been many great inventions, things that changed the way we live. The first great in
• 新鲜红苋菜的叶片呈红色。将其浸泡在凉水里，凉水不会变成红色；将其泡在沸水里，沸水会变成红色。这是因为沸水破坏了红苋菜细胞的什么结构？[]A．细胞壁B．细胞膜C．细胞质D．细-八年级生物
• 阅读理解。Body language is an important part ofcommunication(交流).If you want to communicate well,it'