在自然状态下，某一桦树林中出现了云杉树苗，云杉长大后，高度超过桦树林。桦树不如云杉耐阴，而逐渐减少，最终形成以云杉为主的树林，这种现象是

试卷相关题目

• 1为精子运动提供能量的细胞是

  A.中心粒

  B.线粒体

  C.高尔基体

  D.溶酶体

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• 2下列关于植物激素的叙述，错误的是

  A.根尖能够产生细胞分裂素

  B.脱落酸能抑制马铃薯发芽

  C.生长素的化学本质是蛋白质

  D.赤霉素施用过多可引起水稻植株疯长

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• 3现有与某种植物种子萌发有关的4组实验处理如下表。<table style="BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; BORDER-COLLAPSE: collapse; MARGIN-LEFT: 23.4pt; BORDER-TOP: medium none; BORDER-RIGHT: medium none; mso-border-alt: solid windowtext .5pt; mso-yfti-tbllook: 480; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; mso-border-insideh: .5pt solid windowtext; mso-border-insidev: .5pt solid windowtext" border="1" cellspacing="0" cellpadding="0" _dj="MsoTableGrid"><tbody><tr style="HEIGHT: 16.5pt; mso-yfti-irow: 0; mso-yfti-firstrow: yes"><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 59.4pt; PADDING-RIGHT: 5.4pt; HEIGHT: 16.5pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt" width="79">实验组</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 81.9pt; PADDING-RIGHT: 5.4pt; HEIGHT: 16.5pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" width="109">Ⅰ</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 81.9pt; PADDING-RIGHT: 5.4pt; HEIGHT: 16.5pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" width="109">Ⅱ</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 82.35pt; PADDING-RIGHT: 5.4pt; HEIGHT: 16.5pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" width="110">Ⅲ</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 82.05pt; PADDING-RIGHT: 5.4pt; HEIGHT: 16.5pt; BORDER-TOP: windowtext 1pt solid; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt" width="109">Ⅳ</td></tr><tr style="HEIGHT: 65.2pt; mso-yfti-irow: 1; mso-yfti-lastrow: yes"><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: windowtext 1pt solid; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 59.4pt; PADDING-RIGHT: 5.4pt; HEIGHT: 65.2pt; BORDER-TOP: medium none; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" width="79">处理</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 81.9pt; PADDING-RIGHT: 5.4pt; HEIGHT: 65.2pt; BORDER-TOP: medium none; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="109">种皮完整，25℃蒸馏水浸泡24h</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 81.9pt; PADDING-RIGHT: 5.4pt; HEIGHT: 65.2pt; BORDER-TOP: medium none; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="109">机械破损种皮，25℃蒸馏水浸泡24h</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 82.35pt; PADDING-RIGHT: 5.4pt; HEIGHT: 65.2pt; BORDER-TOP: medium none; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="110">种皮完整,0.05%赤霉素水溶液25℃浸泡24h</td><td style="BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 5.4pt; WIDTH: 82.05pt; PADDING-RIGHT: 5.4pt; HEIGHT: 65.2pt; BORDER-TOP: medium none; BORDER-RIGHT: windowtext 1pt solid; PADDING-TOP: 0cm; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" valign="top" width="109">机械破损种皮，0.05%赤霉素水溶液25℃浸泡24h</td></tr></tbody></table>下列组合不能达到相应目的的是

  A.仅做Ⅰ组与Ⅱ组实验，可探究机械破损对该种子萌发的影响

  B.仅做Ⅰ组与Ⅲ组实验，可探究种皮完整条件下赤霉素对该种子萌发的影响

  C.仅做Ⅱ组与Ⅲ组实验，可探究赤霉素或机械破损对该种子萌发的影响

  D.仅做Ⅱ组与Ⅳ组实验，可探究机械破损条件下赤霉素对该种子萌发的影响

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• 4有关真核细胞DNA复制和转录这两种过程的叙述，错误的是

  A.两种过程都可在细胞核中发生

  B.两种过程都有酶参与反应

  C.两种过程都以脱氧核糖核苷酸为原料

  D.两种过程都以DNA为模板

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• 5有关神经系统的叙述，错误的是

  A.脊髓、脑干属于中枢神经系统

  B.位于大脑皮层的呼吸中枢是维持生命的必要中枢

  C.神经系统调节机体活动的基本方式是反射

  D.高级神经中枢和低级神经中枢对躯体运动都有调节作用

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• 6假设将水稻田里的杂划全部清除掉，稻田生态系统中

  A.水稻害虫密度将下降

  B.能量流动的营养级数减少

  C.水稻固定的太阳能增加

  D.物种多样性上升

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