题干

实验探究题:具有活性的植物细胞在一定条件下可发生质壁分离和复原现象。质壁分离是指植物细胞因水分从液泡中流失,发生的细胞膜以内部分与细胞壁逐渐分离的现象;复原是指细胞恢复成原来的状态。 为比较相同浓度的不同溶液引起植物细胞质壁分离的效果,生物兴趣小组设计了 以下实验:

请回答:

上一题 下一题 0.0难度 选择题 更新时间:2018-01-09 09:11:07

答案(点此获取答案解析)

同类题4

阅读理解

    Japan's youth are losing interest in science and as a result, threatening the nation's industrial progress. According to Japan Science and Technology Agency, young Japanese are surrounded by high-tech devices(设备), but are not interested in how they work.

    Japanese businesses have succeeded partly because they've a great many engineers. A drop in interest could lead to a decline(减少) in their numbers and quality. "In the past, the young had a big interest in science and technology," said Hirano, director of the agency's policy department.

    There are two main reasons for the problem. The first is known as "black box syndrome" of modern technology.

    Electronic devices depend on tiny silicon chips(芯片), which can only be made in big factories, whose workings can't be seen by the eyes. The devices, unlike machines of the past driven by gears and wheels, are simply boxes.

    Young Japanese, brought up on video games and at home with computers, enjoy using modern technology, but this is a passive interest and different from the interest in how things work. "You need an active interest to get interested in science. This is declining in the young," said Hirano.

    About two-thirds of Japanese in their 20s use PCs, twice the number of those in their 50s. But only 40% of those in their 20s say they are interested in news about science and technology, compared to 60% of the 50 to 60 year olds.

    "Another reason for it is that life in modern Japan is too comfortable," he said. "A wealthy society reduces people's desire to modernize and develop their country. To a degree, you can't avoid this when the fruits of science and technology are fully developed." Similarly, science in Europe and the US has also suffered a lack of interest.