求教

sierrapan · 发表于 2009-11-7 16:37:07

Yeasts capable of leavening bread are widespread, and in the many centuries during which the ancient Egyptians made only unleavened bread, such yeasts must frequently have been mixed into bread doughs accidentally. The Egyptians, however, did not discover leavened bread until about 3000 B.C. That discovery roughly coincided with the introduction of a wheat variety that was preferable to previous varieties because its edible kernel could be removed from the husk without first toasting the grain.

Which of the following, if true, provides the strongest evidence that the two developments were causally related?
Even after the ancient Egyptians discovered leavened bread and the techniques for reliably producing it were well known, unleavened bread continued to be widely consumed.

Heating a wheat kernel destroys its gluten, a protein that must be present in order for yeast to leaven bread dough. 为什么是这个，我怎么觉得这个正好否定了问题呢？

Telomerase is an enzyme that is produced only in cells that are actively dividing. For this reason it is generally absent from body tissues in adults. Bone marrow is an exception to this rule, however, since even in adults, bone marrow cells continually divide to replace old blood cells. Cancers are another exception, because their cells are rapidly dividing.
The information provided most strongly supports which of the following?

[table=undefined][tr][td][td]In children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing. 为什么不选这个

The presence of telomerase in bone marrow is no indication of bone marrow cancer.

sierrapan · 发表于 2009-11-7 17:02:38

请指导！

求教

Yeasts的

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