2010年夏季,四川和重庆遭遇百年不遇的特大水灾,有关当地生物与环境之间关系的说法不

题型:单项选择题

问题:

2010年夏季,四川和重庆遭遇百年不遇的特大水灾,有关当地生物与环境之间关系的说法不正确的是()

A.持续降雨会引起当地生物种群增长曲线由“J”型变为“S”型

B.当地植物基因突变产生的某种新性状有可能适应水生环境

C.持续降雨导致生态系统的物种多样性锐减,抵抗力稳定性减弱

D.水分是影响群落水平结构的重要生态因素之一

考点:高中生物种群和群落种群和群落题库
题型:单项选择题
已知向量
a
b
的夹角为60°,且|
a
|=2,|
b
|=1,
(1)求 
a
b
;                  (2)求|
a
+
b
|.
题型:单项选择题

下图中甲、乙、丙、丁四地位于同一纬度,其中昼夜温差最小的是

[ ]

A、甲

B、乙

C、丙

D、丁

题型:单项选择题

在联邦制国家,地方政府财政是指().

A.成员单位政府财政

B.成员单位政府下的地方各级政府财政

C.市政府财政

D.村政府财政

题型:单项选择题

试述厂商比较成本理论。

题型:单项选择题

Passage Three


Being sociable looks like a good way to" add years to your life. Relationships with family, friends, neighbours ,even pets ,will all do the trick ,but the biggest longevity(长寿) boost seems to come from marriage or an equivalent relationship. The effect was first noted in 1858 by William Farr,who wrote that widows and widowers were at a much higher risk of dying than their married peers. Studies since then suggest that marriage could add as much as seven years to a man’s life and two to a woman’s. The effect holds for all causes of death, whether illness, accident or self-harm.
Even if the odds are stacked against you, marriage can more than compensate. Linda Waite of the University of Chicago has found that a married older man with heart disease can expect to live nearly four years longer than an unmarried man with a healthy heart. Likewise, a married man who smokes more than a pack a day is likely to live as long as a divorced man who doesn’t smoke. There’s a flip side, however, as partners are more likely to become ill or die in the couple of years following their spouse’s death, and caring for a spouse with mental disorder can leave you with some of the same severe problems. Even so, the odds favour marriage. In a 30-year study of more than 10,000 people, Nicholas Christakis of Harvard Medical School describes how all kinds of social networks have similar effects.
So how does it work The effects are complex, affected by socio-economic factors, health-service provision,emotional support and other more physiological (生理的)mechanisms. For example, social contact can boost development of the brain and immune system, leading to better health and less chance of depression later in life. People in supportive relationships may handle stress better. Then there are the psychological benefits of a supportive partner.
A life partner,children and good friends are all recommended if you aim to live to 100. The ultimate social network is still being mapped out, but Christakis says:" People are interconnected, so their health is interconnected. \

What can be inferred from the last paragraph

A.It’s important that we develop a social network when young.

B.To stay healthy, one should have a proper social network.

C.Getting a divorce means risking a reduced life span.

D.We should share our social networks with each other.

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