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762. In an attempt to produce a coffee plant that would yield beans containing no caffeine, the synthesis of a substance known to be integral to the initial stages of caffeine production was blocked either in the beans, in the leaves, or both. For those plants in which the synthesis of the substance was blocked only in the leaves, the resulting beans contained no caffeine.
Any of the following, if true, would provide the basis for an explanation of the observed
results EXCEPT:
逻辑链:
P1:咖啡因的产生或者在豆子里,或者在叶片里,或者在这两者中被阻断
C:对于只在叶片中被阻断生产咖啡因的植物,豆子里也不会含有咖啡因
逻辑思路:
这个逻辑链可能犯了**否定前件**的错误,也就是说,从一个条件语句的否定前件推出了否定后件,但这并不一定成立。例如,如果A,则B,不一定意味着如果不A,则不B。
条件语句是:如果咖啡因的产生在豆子里或者在叶片里,或者在这两者中被阻断,那么咖啡因的含量会受到影响。
否定前件是:咖啡因的产生只在叶片中被阻断。您的否定后件是:豆子里不会含有咖啡因。但是,这个推论并不一定正确,因为咖啡因的产生可能还受到其他因素的影响,比如基因表达,代谢途径,环境条件等。
A. In coffee plants, the substance is synthesized only in the leaves and then moves to the beans, where the initial stages of caffeine production take place.
更改了P,将P改为只在叶片里产生,然后转移到豆子
B. In coffee plants, the last stage of caffeine production takes place in the beans using a compound that is produced only in the leaves by the substance.
更改了P,表明第一步仅仅在叶片里合成,最后一步发生在豆子里
C. In coffee plants, the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance.
更改了P,第一次只发生在豆子里,然后第二步只发生在叶片里,而且跟阻断的物质无关,不能推导出结论
D. In coffee plants, caffeine production takes place only in the leaves, but the caffeine
then moves to the beans.
P:只发生在叶片里
Caffeine was produced in the beans of the modified coffee plants, but all of it moved to the leaves, which normally produce their own caffeine.
尽管在豆子里合成,但是豆子里合成的全部移动到叶片里
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