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问题 选择题

某校生物兴趣小组11人到野外捕捉蝴蝶制作标本．其中有2人每人捉到6只，有4人每人捉到3只，其余5人每人捉到4只，则这个兴趣小组平均每人捉到蝴蝶只数为（  ）

A．3

B．4

C．5

D．6

答案

答案：B

这个兴趣小组平均每人捉到蝴蝶只数，所以选B

选择题

下列关于真核细胞生物膜的叙述，正确的是[ ]

A．生物膜的特定功能主要由膜蛋白决定

B．构成膜的脂质主要是磷脂、脂肪和胆固醇

C．有氧呼吸及光合作用产生ATP均在膜上进行

D．核糖体、内质网、高尔基体的膜都参与蛋白质的合成与运输
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单项选择题 共用题干题

● A glue that holds the whole Internet together is the network layer protocol, (71)．Unlike most older network layer protocols, it was designed from the beginning with internetworking in mind．Its job is to provide a (72) way to transport datagrams from source to destination，without regard to whether these machines are on the same network or whether there are other networks in between them． Communication in the Internet works as follows．The (73) layer takes data streams and breaks them up into datagrams．Each datagram is transmitted through the Internet, possibly being fragmented into smaller units as it goes．When all the pieces finally get to the destination machine, they are reassembled by the (74) layer into the original datagram．This datagram is then handed to the transport layer, which inserts it into the receiving process’ input stream． An IP datagram consists of a header part and a text part．The header has a (75) part and a variable length optional part．

空白处（72）应选择（）

A.best-quality

B.quality-guaranteed

C.connection-oriented

D.best-efforts
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