相貌离不开皮肤,尤其颜面部的皮肤 与美容的极其密切。皮肤的颜色主要取 决于表皮黑色素的含量。但表皮的厚薄 ,胡萝卜素等含量的多少,真皮血管的 血液供应也影响皮肤的颜色。 从生物学角度看,头发及毛发,甚至 指甲都可视为皮肤的延伸

八、物理学危机与物理学革命 九、原子内部世界的探索 十、20世纪的化学及其发展 十一、现代生物科学成就 十二、环境科学的兴起 十三、系统科学思想与方法

1.正确识别各种类型茎 2.正确识别各种类型变态茎 3.区别攀援茎与缠绕茎、匍匐茎和平卧茎 4.茎在外形上与根的区别 5.解释概念:树皮周皮

病毒性皮肤病是由病毒感染所致的皮肤粘膜病变。根据病毒 性皮肤病的不同临床表现特点,可将其分为新生物型、疱疹 型、红斑发疹型。单纯疱疹是由单纯疱疹病毒感染所致的病 毒性皮肤病。皮疹以群集性小水疱为特征,能引起多种部位 感染,但以口周、鼻腔、生殖器等处好发。病程有自限性

一、25种能源 太阳能、风能、水能、生物质能、地热 能、海洋温差、海洋波力能、海洋动力 能、煤炭、石油、天然气、油页岩、原 子核能 ·煤气、电力、蒸汽、液化气、汽油、重 油、柴油、沼气、电池、煤油、焦炭、 氢气

The number of abdominal segments: Primitively, abdomen is 11-segmented and the terminal segments are usually modified and/or diminished.原始昆虫腹部一般12节(11腹节+ 尾节) Most insects have 9 or 10 abdominal segments, but several of these are reduced

Welcome to the course, which is an introduction to cultural or sociocultural anthropology We will have two lectures and one discussion a week Most of the requirements (a final exam, series of six papers adding up to about twenty pages; at least an hour a week of discussion)is set by the MIT Humanities Distribution system

Ethnography 1. INTRO Originally people who studied cultures were amateurs who happened to either be particularly observant or who happened to travel a lot. Some of them did more or less what people did today. a. Ibn Khaldun was a famous Arab scholar who did observations of everyone, including the Vikings

1.单细胞植物,一个细胞代表了一个个体,一切生命活动,包括新陈代谢、 生长发育、繁殖,均由一个细胞完成。复杂的高等植物,一个个体由无数 细胞组成,细胞之间有了机能和形态结构的分工,相互依存、彼此协作, 共同保证有机体的正常生命活动

任何植物体,单细胞的藻类,到参天大树,都是通过细胞分裂,增加细胞的数目,使植物体能完成从生长发育到繁殖的整个生命过程。细胞分裂主要有三种方式:有丝分裂mitosis,无丝分裂 amitosis和减数分裂 meiosis