下列关于内环境稳态的叙述,错误的是[ ] A.内环境的理化性质是相对稳定的 B.

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问题:

下列关于内环境稳态的叙述,错误的是[ ]

A.内环境的理化性质是相对稳定的

B.内环境稳态是由体内各种调节机制所维持的

C.内环境的理化性质是恒定不变的

D.内环境稳态不能维持,机体的生命活动就会受到威胁

考点:内环境的稳态
题型:选择题
△ABC中,若a=5,b=3,C=
3
,则c=______.
题型:选择题

以下哪个不是风险分析的主要内容?()

A.根据威胁的属性判断安全事件发生的可能性。

B.对信息资产进行识别并对资产的价值进行赋值。

C.根据安全事件发生的可能性以及安全事件的损失,计算安全事件一旦发生对组织的影响,即风险值。

D.对资产的脆弱性进行识别并对具体资产脆弱性的严重程度赋值。

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(1)求磁铁第一次到达B处的速度大小。

(2)求磁铁在BC上向上运动的加速度大小。   

(3)请分析判断磁铁最终能否第二次到达B处。

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Beijing: The United States and North Korea had their first ________in four months here this afternoon as part of the ________negotiations on how to end North Korea’’s nuclear program, but diplomats played down prospects for________.James A. Kelly, assistant________, and Kim Yong II, North Korea’’s deputy foreign minister, met ________of formal discussions, ________on direct dialogue that began after a stormy meeting ________in which North Korea warned that it was moving quickly to ________nuclear arms.The Bush administration had insisted ________that it would only hold talks with North Korea ________because, it argued, only ________pressure would persuade North Korea to________. It got its way when North Korea dropped its insistence on ________and agreed, after extensive efforts by China, to hold unusual simultaneous negotiations with ________,________,________and ________as well as the United States.Though Bush administration officials had not ________talking privately with the North Koreans during________, the fact that Mr. Kelly and Mr. Kim met on the first day was seen as a sign of ________by the American side.

题型:选择题

1958年美国人斯图尔特将胡萝卜细胞培养成一株新的植株,从而证实了植物细胞全能性。下列相关叙述不正确的是:()

A.已分化的细胞仍具有形成完整植株所需要的全套基因

B.细胞全能性体现过程中受到基因和环境的共同影响

C.已分化的细胞在结构和功能上的特化不能逆转

D.理论上植物体中每个活细胞都具有细胞全能性

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