搜题请搜索小程序“爱下问搜题”
问题 多项选择题

下列有关生态恢复的内容，表述正确的有( )。

A．生态恢复是相对于生态破坏而言的，生态破坏可以理解为生态系统的结构发生变化、功能退化或丧失，关系紊乱

B．生态恢复技术的基础是生态系统的群落演替

C．生态恢复就是恢复系统的合理结构、高效的功能和协调的关系

D．生态恢复最本质的目的是恢复系统的必要功能并达到系统自维持状态

答案

参考答案：A,C,D

单项选择题

Ink-jet printer belongs to nonimpact printers in which the characters are formed by projecting particles or droplets of ink on to paper. (71) printer is also a nonimpact printer in which the characters are produced by applying hot elements to heat-sensitive paper directly or by melting ink from a (72) on to plain paper. Electrostatic printer creates an electrostatic latent image, which is then made visible by a toner and transferred and fixed on paper. An electrostatic printer may be used in some instances as a (73) . Laser printer creates, by means of a laser beam directed on a (74) surface, a latent image which is then made visible by a toner and transferred and fixed on paper. Magnetographic printer creates, by means of magnetic heads operating on a metallic drum, a latent image which is then made visible by a toner and transferred and fixed on paper. Computer-output-microfilm (COM) printer produces on a photographic film a (75) of each page.

（75）处填（）。

A．microimage

B．holograph

C．thumbnail

D．bitmap
查看答案
单项选择题

哪种方法不是加保护层防腐蚀措施（）。

A.气体保护层

B.金属保护层

C.非金属保护层

D.非金属保护膜
查看答案