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“SARS”病毒的遗传物质中含有核苷酸的种类及碱基的种类分别是（  ）

    Hello!My name is Bob. My classroom is not big but nice. There are 21 desks and 20 chairs. 墙上有一些画和一幅地图。Mrs Brown is our English teacher. She is from a big city.She is nice. Her husband Mr Brown is a teacher too, but he isn't in our school. Tom is my good friend. We like playing football on Saturday. Where is my football? It is under my desk.     

信徒称为穆斯林的宗教产生于（   ）

有人总结某种大众传媒的特点：第一，信息较为详细，可以获得比较系统的信息。第二，信息具有可选择性。第三，信息具有可保留性。第四，信息成本低廉，不必一次性投入大量资金。这种传媒是（    ）