问题
单项选择题
男，8岁。右足底被铁锈钉刺伤12天，出现张口困难，继之出现苦笑面容，角弓反张，声响及触碰病人可诱发上述症状，神志清楚，无发热。
该病致病菌属于
A．革兰阴性大肠杆菌
B．革兰阴性厌氧拟杆菌
C．革兰阴性变形杆菌
D．革兰阳性梭形芽孢杆菌
答案
参考答案：D
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男，8岁。右足底被铁锈钉刺伤12天，出现张口困难，继之出现苦笑面容，角弓反张，声响及触碰病人可诱发上述症状，神志清楚，无发热。
该病致病菌属于
A．革兰阴性大肠杆菌
B．革兰阴性厌氧拟杆菌
C．革兰阴性变形杆菌
D．革兰阳性梭形芽孢杆菌
参考答案：D
| The blue of the sea is caused by the scattering of sunlight by tiny particles suspended in the water. Blue light, being of short wavelength, is scattered more efficiently than light of longer wavelengths. Although waters of the open ocean are commonly some shade of blue, green water is commonly seen near coasts, especially in tropical or subtropical regions. This is caused by yellow pigments being mixed with blue water. Phytoplankton are one source of the yellow pigment. Other microscopic plants may color the water brown or brownish-red. Near the shore, silt or sediment in suspension can give water a brownish hue. Outflow of large rivers can often be observed many miles offshore by the coloration of suspended soil particles. Marine phytoplankton (Greek for "plant wanderers") are microscopic single-celled plants that include diatoms, dinoflagellates, coccolithophorids, green algae, and blue-green algae, among others. The growth of these organisms, which photosynthesize light, depends on a delicate balance of nutrient enrichment via vertical mixing, which is often limited by the availability of nitrogen and light. Diatoms are one-celled plants with patterned glass coverings. Each glass, or silicon dioxide box, is ornamented with species-specific designs, pits, and perforations making them popular with microscopists and, more recently, electron scanning microscopists. |
What can give waters a brownish hue near the shore
A．Sediment.
B．Phytoplankton.
C．Blue pigment.
D．Diatoms.