单选题在骨骼肌神经一肌接头处，消除乙酰胆碱的酶是

单选题It's not only humans that flourish in large settlements. Some ants find urban life so accommodating that their populations explode and they form supercolonies in cities. "One of the most common house ant species might have been built for living in some of the smallest spaces in a forest, but the ants have found ways to take advantage of the comforts of city living," Purdue University said in a statement. Grzegorz Buczkowski, a Purdue University research assistant professor of entomology, discovered odorous house ants live in supercolonies, creating complex networks entomologists have never seen with the species before now. He found that odorous house ant colonies become larger and more complex as they move from forest to city and act somewhat like an invasive species, the university said. "The ants live about 50 to a colony with one queen in forest settings but explode into supercolonies with more than 6 million workers and 50 000 queens in urban areas," the university explained. "This is a native species that's doing this," said Buczkowski, whose results are published in the early online version of the journal Biological Invasions. "Native ants are not supposed to become invasive. We don't know of any other native ants that are outcompeting other species of native ants like these," Buczkowski said. Odorous house ants live in hollow acorn shells in the forest. They're called odorous because they have a coconut (椰子)-or rum-like smell when crushed. They're considered one of the most common house ants, Purdue said. In semi-natural areas that are a cross of forest and urban areas, such as a park, Buczkowski said he observed colonies of about 500 workers with a single queen. "It's possible that as the ants get closer to urban areas they have easier access to food, shelter and other resources," he said. "In the forest, they have to compete for food and nesting sites," Buczkowski said. "In the cities, they don't have that competition. People give them a place to nest, food to eat. " Buczkowski observed the ants in three different settings on and around the Purdue campus. He said it might be expected that if the odorous house ants were able to multiply into complex colonies, other ants would do the same. But Buczkowski found no evidence that other ants had adapted to new environments and evolved into larger groups as the odorous house ants have, Purdie said. "It's possible that odorous house ants are better adapted to city environments than other ant species or that they had somehow outcompeted or dominated other species," he said. "This raises a lot of questions we'd like to answer. " Buczkowski said understanding why the supercolonies form could lead to better control of the pests in homes, as well as ensuring that they don't outcompete beneficial species. Future studies on odorous house ants will include studying the ant's genetics and trying to understand the effects of urbanization of odorous house ants, Purdue said.

单选题O型血血清与其他型红细胞相混时( ) A．无任何反应 B．将会发生凝集反应 C．将会出现凝固 D．将会发生红细胞叠连 E．将会发生出血现象

单选题支配消化道的交感神经节后纤维末梢释放的神经递质是( ) A．ACh B．去甲肾上腺素 C．多巴胺 D．肾上腺素 E．γ-氨基丁酸

单选题不符合上题患者疾病的合并证的描述是

单选题下列各项中，与组织液生成无关的因素是 A．毛细血管血压 B．静脉压 C．组织液胶体渗透压 D．血浆晶体渗透压

单选题关于测定机体产热量的有关概念，正确的是( ) A．糖的卡价最大 B．一般膳食的呼吸商为0.82 C．脂肪氧热价最高 D．蛋白质呼吸商最大

单选题坏死组织本身的结局下列哪一项是错误的( )(1989年)

单选题A．脑干网状结构B．视前区－下丘脑前部C．下丘脑后部D．隔区E．杏仁核

单选题由损伤周围的同种细胞增殖来完成修复的过程称______

单选题A．牢固的止血栓B．松软的止血栓C．两者都是D．两者都不是 (1998年)

单选题总和的结构基础为( ) A．单线式联系 B．辐散式联系 C．聚合式联系 D．环状联系 E．链锁式联系

单选题血浆品体渗透压的形成主要决定于血浆中的

单选题泌尿道最常见的恶性肿瘤是

单选题A．KCI B．NaCl C．尿素 D．尿素和NaCl

单选题急性感染性心内膜炎最常见的病原体是______

单选题 肺泡膜病变导致呼吸衰竭的主要机制是 ( ) A、弥散障碍 B、Pa02升高 c、肺泡V/Q比值升高 D、呼吸耗能升高 E、肺泡气P02下降

单选题下列中最常见的乳腺癌病理学类型是( )(1994年)

单选题 流行性乙型脑炎的病原体是 ( ) A、乙型链球菌 B、α-溶血性链球菌 C、脑膜炎双球菌 D、乙型脑炎病毒 E、柯萨奇病毒

单选题呼吸商最高的营养物质是