题目

Drawings of human colonies on other planets often picture the entire community under a glass or plastic bubble．The bubble is intended to create an atmosphere with adequate oxygen and other essential elements．But similar bubble-like structures have also been constructed on earth．One of the most famous, and controversial, is a site in the Arizona desert． Biosphere 2, as it is called, was built not far from Tucson in 1984 and is now run by Columbia University．This huge（7,200,000-cubic-foot）glass and steel construction contains several separate ecosystems, including a desert,细胞膜的结构特点是具有一定的流动性，下列实例中能反映该特点的是（　　）①高尔基体形成的小泡与细胞膜融合；②吞噬细胞吞噬病菌；③小肠绒毛上皮细胞对Na+、K+的吸收；④核糖体中合成的蛋白质进入细胞核；⑤变形虫能出伪足． A、①②④B、②③④C、①②④⑤D、①②⑤