题干

学习了种子萌芽的条件后,小明突然想到一个问题:吃西瓜时为什么没看到过有萌发的种子,而扔在地上的西瓜种子却会很快萌发呢?于是小明与学习小组的同学一起进行了分析,大家首先根据书本知识,提出了以下假设:

假设一:种子在西瓜内缺乏萌发所需的温度;

假设二:种子在西瓜内缺乏萌发所需的水分;

假设三:种子在西瓜内缺乏萌发所需的空气;

经过理性的思考和讨论,大家认为上述假设中有两个难以成立,你认为假设____ 不成立(写出一个即可),理由是____ .

通过查阅相关资料,他们了解到许多植物的种子成熟后都有休眠的现象,即种子在适宜的条件下仍不能萌发,这是植物重要的适应特征之一.而导致种子休眠的原因很多,西瓜内种子不能萌发是由于果实中存在抑制物质.

为了验证上诉资料是否可信,他们决定对此展开研究,请你与他们一起完成探究过程:

①将一个成熟的西瓜切开,取出里面的种子并洗净,将瓜瓤捣碎后过滤,西瓜汁备用.

②取两个培养皿,分别贴上注有A、B的标签,每个培养皿中均放入多层滤纸,滤纸上各放10颗西瓜种子.

③在培养皿A中的滤纸滴加一定量的清水,在培养皿B中的滤纸上滴加____ .

④将两个培养皿放在温度适宜的环境中,每天添加水或西瓜汁,以保持滤纸湿润,连续观察多天,结果如下:西瓜种子萌发数量记录表

 培养皿

 第1天

 第2天

第3天

 第4天

第5天 

第6天 

第7天 

 A

0

 0

1

 5

7

 9

 9

 B

0

 0

0

0

0

 0

 0

通过上述实验,你认为他们找到的资料是否可信?____ .

上一题 下一题 0.0难度 选择题 更新时间:2019-09-08 10:46:26

答案(点此获取答案解析)

二,西瓜内含有足够的水分,西瓜汁,可信

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    Paying a higher price than usual for a ticket to see a film in 3D is the annoyance of many a cinema-goer's life.

    But there may be a benefit to doing so, as a study has found that 3D films exercise the brain and improve short-term functioning in a similar way to brain-training tests.

    The research found that people who watched a movie in 3D improved cognitive (认知) skills, compared to those who watched it in 2D.

    The research was led by neuroscientist(神经学家) Dr Patrick Fagan from Goldsmiths University in London. More than 100 people took part in the experiment, where participants watched Disney film Big Hero 6 in either standard format or RealD 3D.

    They also carried out a brain-training-style test before and after seeing a section from the film. The test covered memory, reaction times and cognitive function and the results were compared later.

    According to the research, which was carried out in partnership with science group Thrill Laboratory, participants experienced a 23 percent increase in cognitive processing, as well as an 11 percent increase in reaction times.

    Dr Fagan said that the results showed enough of an improvement in brain function to suggest that 3D could play a part in improving brain power in the future.

    "These findings are more significant than you might think," he said. "It is a fact that people are living longer and there is a noticeable decline in cognitive brain function in old age which can worsen future quality of life. There has never been a better time to look at ways to improve brain function. The initial results of this study show that 3D films may potentially play a role in slowing this decline."

    A second part of the experiment involved those watching the film being fitted with headsets that scanned brain activity and this too showed heightened (加强的) activity when watching 3D. According to the results, participants were seven percent more engaged with what they were watching, adding to argument that 3D movies are more like watching real-life—something Professor Brendan Walker from Thrill Laboratory agreed with.

    "As Professor Brendan Walker's test concluded, 3D films are more attractive and heighten the senses — this, in turn, makes the brain run at quicker speeds," Dr Fagan said.