单位浓度的微量变化所引起指示物理量的变化，这种变化被称作（）

搜题请搜索小程序“爱下问搜题”

问题单项选择题

A.精密度

B.准确度

C.检测极限

D.灵敏度

E.特异性

答案

参考答案：D

解析：灵敏度为某方法对单位浓度或单位量待测物质变化所产生的响应量的变化程度。

选择题

In modern times, people are facing all kinds of _____ although they are leading a comfortable life.

A．pressures

B．opinions

C．characters

D．stress

查看答案

单项选择题

Since life began eons ago, thousands of creatures have come and gone. Some, such as the dinosaurs, became extinct due to naturally changing ecologic conditions. More recent threats to life forms are humans and their activities. Man has drained marshes, burned prairies, dammed and diverted rivers. Some of the more recent casualties of man’’s expansion have been the dodo, great auk, passenger pigeon, Irish elk, and Steller’’s sea cow. Sadly, we can no longer attribute the increasing decline in our wild animals and plant species to "natural" processes. Many species are dying out because of exploitation, habitat alteration or destruction, pollution, or the introduction of new species of plants and animals to an area. As mandated by Congress, protecting endangered species, and restoring them to the point where their existence is no longer jeopardized, is the primary objective of the U.S. Fish and Wildlife Service’’s Endangered Species Program.

The tone of this passage is________.

A．nationalistic

B．pro-wildlife

C．anti-wildlife

D．feminist

查看答案