更多"[不定项选择题]白细胞减少症是指外周血白细胞数持续低于"的相关试题:
[不定项选择题]白细胞减少症的诊断标准是指外周血白细胞总数低于（ ）。
A.0.5×10^9/L
B.4.0×10^9/L
C.1.5×10^9/L
D.3.0×10^9/L
E.0.2×10^9/L
[单选题]白细胞减少症是指外周血白细胞计数持续低于
A.0.5*109/L
B.1.0*109/L
C.2.0*109/L
D.3.0*109/L
E.4.0*109/L
[不定项选择题]正常前列腺液白细胞数每高倍视野不超过
A.2个
B.3个
C.5个
D.8个
E.10个
[不定项选择题]白细胞减少是指外周血白细胞绝对值持续低于（ ）。
A.4.0×109/L
B.3.0×109/L
C.2.0×109/L
D.1.0×109/L
E.0.5×109/L
[不定项选择题]治疗哮喘持续状态宜选用
A.氨茶碱
B.麻黄碱
C.糖皮质激素
D.异丙肾上腺素
E.以上都不是
[不定项选择题]癫痫持续状态表现为（ ）。
A.局部抽搐持续数小时或数日
B.持续性运动性发作
C.长时间失神性发作
D.发作间歇期内患者持续昏迷
E.强直-阵挛性反复发作
[不定项选择题]持续性部分性癫痫发作表现为（ ）。
A.局部抽搐持续数小时或数日
B.持续性运动性发作
C.长时间失神性发作
D.发作间歇期内患者持续昏迷
E.强直-阵挛性反复发作
[不定项选择题]癫痫持续状态的首选药物是（ ）。
A.地西泮
B.扑米酮
C.丙戊酸钠
D.卡马西平
E.苯巴比妥
[不定项选择题]癫痫持续状态引起发热的病因是查看材料
A.药物热
B.机体产热过多
C.感染的伴发症状
D.非感染的继发后果
E.传染性疾病所伴发症状
[不定项选择题]癫痫持续状态的首选药是（ ）。
A.苯妥英钠
B.地西泮
C.乙琥胺
D.丙戌酸钠
E.卡巴西平
[不定项选择题]癫痫的药物治疗癫痫持续状态首选
A.卡马西平
B.丙戊酸钠
C.苯妥英钠
D.拉莫三嗪
E.地西泮
[不定项选择题]共用题干
Ants Have Big Impact on Environment as“Ecosystem Engineers”
Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as“ecosystem engineers”and predators.The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.
Firstly,through moving of soil by nest building activity and by collecting food they af-fect the level of nutrients in the soil.This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.
Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.
Dirk Sanders,an author of the study from the university's Centre for Ecology and Con-servation,said:“Ants are very effective predators which thrive in huge numbers. They're al-so very territorial and very aggressive,defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area.”
“In this research,we studied for the first time how big this impact is and the subtleties of it.What we found is that despite being predators,their presence can also lead to an in-crease in density and diversity of other animal groups. They genuinely play a key role in the local environment,having a big influence on the grassland food web,”Sanders said.
The study,carried out in Germany,studied the impact of the presence of different com-binations and densities of black garden ants and common red ants,both species which can be found across Europe,including in the UK.It found that a low density of ants in an area in-creased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.
Dr Frank van Veen,another author on the study,said:“What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counter-acting the positive influence via ecosystem engineering.”
Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers.Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obvi-ously reduces its richness. However,it is not clear how such disturbance damages the main-tenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.
What does paragraph 6 tell us?
A.Ants bring about a negative influence to an area when their population is small.
B.Ants bring about a positive influence to an area when their population is small.
C.Ants'predation counteracts the positive influence they may have on an area.
D.At higher density,ants produce a positive influence on an area.
