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【多选题】
What is nitrogen cycle?A.
In the biosphere, the metabolic processes of different species function interdependently to salvage and reuse biologically available nitrogen in a vast nitrogen cycle.
B.
The first step in the cycle is fixation (reduction) of atmospheric nitrogen by nitrogen-fixing bacteria to yield ammonia (NH 3 or NH 4 + ). Although ammonia can be used by most living organisms, soil bacteria that derive their energy by oxidizing ammonia to nitrite (NO 2 ˉ ) and ultimately nitrate ( NO 3 ˉ) are so abundant and active that nearly all ammonia reaching the soil is oxidized to nitrate. This process is known as nitrification.
C.
Plants and many bacteria can take up and readily reduce nitrate and nitrite to ammonia through the action of nitrate and nitrite reductases. This ammonia is incorporated into amino acids by plants. Animals then use plants as a source of amino acids to build their proteins. When organisms die, microbial degradation of their proteins returns ammonia to the soil, where nitrifying bacteria again convert it to nitrite and nitrate.
D.
A balance is maintained between fixed nitrogen and atmospheric nitrogen by bacteria that reduce nitrate and nitrite to N 2 under anaerobic conditions, a process called denitrification. These soil bacteria use NO 3 ˉ or NO 2 ˉ rather than O 2 as the ultimate electron acceptor in a series of reactions that (like oxidative phosphorylation) generates a transmembrane proton gradient, which is used to synthesize ATP.
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【单选题】高血压时心脏向心性肥大指
A.
左室心肌肥厚而心腔不扩张
B.
左室心肌肥厚而心腔扩张
C.
左室壁厚正常而心腔明显扩张
D.
左室左房心肌明显肥厚
E.
左右心室心肌均肥厚
【单选题】关于函数“pulseIn(pin,value)”说法错误的是( )
A.
pin为需要读取脉冲的端子
B.
value为需要读取脉冲的类型
C.
value的值可以是HIGH或LOW
D.
value的值可以是0~255
【单选题】关于函数“pulseIn(pin,value)”说法错误的是( )
A.
pin为需要读取脉冲的端子
B.
pin必须是具备PWM功能的端子
C.
value为需要读取脉冲的类型
D.
value的值可以是HIGH或LOW
【单选题】下列关于Arduino中函数pulseIn(pin,value,timeout)的说法错误的是
A.
参数pin为要读取脉冲宽度的引脚编号
B.
参数value为要读取的脉冲形式（高/低脉冲）
C.
返回值代表脉冲持续时间，单位为ms
D.
参数timeout为超时时间，Arduino在超时时间内没有读取到脉冲信号，将返回0
【单选题】下列关于Arduino中函数pulseIn(pin,value,timeout)的说法错误的是
A.
参数pin为要读取脉冲宽度的引脚编号
B.
参数value为要读取的脉冲形式（高/低脉冲）
C.
返回值代表脉冲持续时间，单位为ms
D.
参数timeout为超时时间，Arduino在超时时间内没有读取到完整脉冲信号，将返回0
【单选题】在日本帝国主义的诱降下,国民党内亲日派头子汪精卫公开叛国投敌,当了汉奸。1940年3月,日本扶持他在( )成立伪国民政府。
A.
上海
B.
南京
C.
武汉
D.
重庆
【单选题】-- Does your grandma live______ --No, but she still feels______.
A.
alone; alone
B.
alone; lonely
C.
lonely; lonely
D.
lonely; alone
【多选题】穿越时光隧道,你回到了南宋都城临安,在下列各项中,可以看到的有( )
A.
城里有精美的瓷器出售
B.
在“瓦子”里有人在说书，有人在看京剧表演
C.
有人在使用纸币购物
D.
人们在阅读《红楼梦》
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