题目

We all dream although we remember only a few of our dreams. Some people train themselves to remember their dreams. As soon as they wake up, they record what their dreams were about. Scientists believe that we have different kinds of sleep. One kind is called R.E.M. R.E.W. stands for rapid eye movement. During this kind of sleep our eyes move quickly, even though they are closed. Although we are asleep, there is a lot of brain activities. We probably have dreams at this time. Sometimes people talk in their sleep. In these dreams the dreamer is usually unhappy or worried about something.19世纪德国M.J.Schleiden和T.Schwann等科学家提出了细胞学说，下列对“细胞学说”理解合理的是( ) ①一切生物都是由细胞和细胞产物构成的 ②细胞是一个相对独立的有机体③提出了细胞膜结构的流动镶嵌模型 ④揭示细胞的统一性和生物体结构的统一性⑤认识到细胞的多样性 ⑥标志着生物学研究进入细胞水平A．①②⑤⑥ B．①②③④ C．③⑤ D．②④⑥