PREP1-15-Q50

evelyn205205

Dendrochronology, the study of tree-ring records to glean information about the past, is possible because each year a tree adds a new layer of wood between the existing wood and the bark.In temperate and subpolar climates, cells added at the growing season's start are large and thin-walled, but later the new cells that develop are smaller and thick-walled; the growing season is followed by a period of dormancy.When a tree trunk is viewed in cross section, a boundary line is normally visible between the small-celled wood added at the end of the growing season in the previous year and the large-celled spring wood of the following year's growing season.The annual growth pattern appears as a series of larger and larger rings.In wet years rings are broad; during drought years they are narrow, since the trees grow less.Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.

However, trees that grew in areas with a steady supply of groundwater show little variation in ring width from year to year; these "complacent" rings tell nothing about changes in climate.And trees in extremely dry regions may go a year or two without adding any rings, thereby introducing uncertainties into the count.Certain speciessometimes add more than one ring in a single year, when growth halts temporarily and then starts again.

Question #50.341-02(23608-!-item-!-188;#058&000341-02)

The passage suggests which of the following about the ring patterns of two trees that grew in the same area and that were of different, but overlapping, ages?

(A) The rings corresponding to the overlapping years would often exhibit similar patterns.
(B) The rings corresponding to the years in which only one of the trees was alive would not reliably indicate the climate conditions of those years.
(C) The rings corresponding to the overlapping years would exhibit similar patterns only if the trees were of the same species.
(D) The rings corresponding to the overlapping years could not be complacent rings.
(E) The rings corresponding to the overlapping years would provide a more reliable index of dry climate conditions than of wet conditions.

答案是A，不理解从文章中式如何得到两者相似的结论的。
期待各路NN哦~谢谢！

evelyn205205

求解求解

evelyn205205

NN们，麻烦了，帮我解释解释吧，谢谢啦~

evelyn205205

没有人帮帮我么？

glhelr

我认为是这样：
这个题目应该要理解这句话哈~“The annual growth pattern appears as a series of larger and larger rings.In wet years rings are broad; during drought years they are narrow, since the trees grow less.Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.”
 其实简单的说就是说了这么一个事：“ 年轮在不同的气候条件下长的不同。所以呢，只要两棵树生长的时间有重叠，但不完全相同，我们就可以判别出当时的气候条件了。” 如果这两棵树在相同的年月中年轮的样子不同，那么我们没有了判断的起点，自然就没法看气候了。

evelyn205205

THX, 斑竹~~~