Reading Comprehension

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 isnormally visible between the small-celled wood added at the end of the growing season in the previous yearand 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 ringwidth 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 species sometimes add more
than one ring in a single year, when growth halts temporarily and then starts again.

52. The passage is primarily concerned with
(A) evaluating the effect of climate on the growth of trees of different species
(B) questioning the validity of a method used to study tree-ring records
(C) explaining how climatic conditions can be deduced from tree-ring patterns
(D) outlining the relation between tree size and cell structure within the tree
(E) tracing the development of a scientific method of analyzing tree-ring patterns

My ans is E which is wrong. I know the OA but still cannot relate it to the passage. I feel that in a case where (A) causes (B) the OA is doing the reverse i.e. (B) causing (A). OA to be revealed soon.

Also, thanks for your valuable input in advance but please justify your answers.

Hi,

I think the answer is C

The first passage talks about how patterns develop and the relation it has with climatic conditions.
The second passage talks about how climatic conditions can affect the count of tree rings.

In essence the whole passage is an explanation.


(A) evaluating the effect of climate on the growth of trees of different species
There is no evaluation here.

(B) questioning the validity of a method used to study tree-ring records
There is no questioning of a method here.

(C) explaining how climatic conditions can be deduced from tree-ring patterns
This seems right

(D) outlining the relation between tree size and cell structure within the tree
The first paragraph touches upon it but it is not the essence of the whole passage

(E) tracing the development of a scientific method of analyzing tree-ring patterns
There is no tracing of the development of a scientific method. There is no discussion about how dendrochronology started, issues and challenges, and so on.

Regards
Anup