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举一反三
【单选题】There are approximately three quarters of a ton of termites (白蚁) for every person on Earth. It now turns out that these critters may be helping to alter the climate and affect man’s life. For years sc...
A.
It is the production by termites that is now of greater concern.
B.
What scientists worry more about is the output from burning fuels.
C.
The output from burning fuels is now rising steadily.
D.
The burning of fuels generates much less carbon dioxide than termites do.
【单选题】异化扩散是指( )
A.
当同种物质、不同浓度的两种溶液相邻地放在一起时,溶质分子顺着浓度差或电位差产生净流动。
B.
在载体蛋白作用下,从高浓度一侧向低浓度一侧转运。
C.
细胞通过某种耗能过程,将物质分子或离子逆着浓度差或电位差由膜的一侧移向另一侧的过程。
D.
大分子物质/大分子团块还能通过出胞(例如,腺细胞分泌某些酶和粘液)和入胞(例如侵入动物体内的细菌、病毒或大分子蛋白质等)两种方式进行转运。