在图所示的电路中，电源电压保持不变。闭合电键S，当滑动变阻器的滑片P向左移动时，

在一定生产规模限度内，随产量增减成正比例变化的是（）。

A．固定成本

B．单位固定成本

C．变动成本

D．单位变动成本

《汉谟拉比法典》

The most damning thing that can be said about the world’s best-endowed and richest country is that it is not only not the leader in health status, but that it is so low in the ranks of the nations. The United States ranks 18th among nations of the world in male life expectancy at birth, 9th in female life expectancy at birth, and 12th in infant mortality. More importantly, huge variations are evident in health status in the United States from one place to the next and from one group to the next.

The forces that affect health can be divided into four groupings that lend themselves to analysis of all health problems. Clearly the largest group of forces resides in the person’s environment. Behavior, in part derived from experiences with the environment, is the next greatest force affecting health. Medical care services, treated as separate from other environmental factors because of the special interest we have in them, make a modest contribution to health status. Finally, the contributions of heredity to health are difficult to judge.

No other country spends what we do per capita for medical care. The care available is among the best technically, even if used too freely and thus dangerously. Given the evidence that medical care is not that valuable and access to care not that bad, it seems most unlikely that our bad showing is caused by the significant proportion who are poorly served. Other hypotheses have greater explanatory power: excessive poverty, both actual and relative, and excessive wealth.

Excessive poverty is probably more prevalent in the U. S. than in any of the countries that have a better infant mortality rate and female life expectancy at birth. This is probably true also for all but four or five of the countries with a longer male life expectancy. In the notably poor countries that exceed us in male survival, difficult living conditions are a more accepted way of life and in several of them, a good basic diet, basic medical care and basic education, and lifelong employment opportunities are an everyday fact of life. In the U. S. a national unemployment level of 10 percent may be 40 percent in the ghetto while less than 4 percent elsewhere. The countries that have surpassed us in health do not have such severe problems. Nor are such a high proportion of their people involved in them.

Excessive wealth is not so obvious a cause of ill health, but, at least: until recently, few other nations could afford such unhealthful ways of living. Excessive intake of animal protein and fats, and use of tobacco and drugs, and dangerous recreational sports and driving habits are all possible only when one is wealthy. Our heritage, desires, and opportunities, combined with the relatively low cost of bad foods and speedy vehicles, make us particularly vulnerable. Our unacceptable health status, then, will not be improved appreciably by expanded medical resources nor by their redistribution so much as by a general attempt to improve the quality of life for all.

Which of the following questions does the passage provide information to answer（）

A. What is the most powerful influence on the health status of a population

B. Which nation in the world leads in health status

C. Is the life expectancy of males in the U.S. longer than that of females

D. What are the most important genetic factors influencing the health of an individual

局成立物资集中采购领导小组。组长由分管物资工作的（）和（）担任；成员由财务部、监察部、法律事务部、检测中心、物资管理部门主要负责人和局物资公司总经理组成。

经营性物业抵押贷款在按一般授信业务的规定进行贷后检查的同时，还应关注（）。

A.是否应华夏银行要求在华夏银行开立资金监管专户，并严格按照借款合同约定的用途使用贷款。

B.物业出租状况

C.抵押物价值变动情况

D.以上都是