In some types of pine tree, a thick layer of needles protects the buds from which new growth proceeds; consequently they are able to withstand forest fires relatively well.
(This question is from Official Guide. Therefore, because of copyrights, the complete question cannot be copied here. The question can be accessed at GMAT Club)
The sentence structure is:
- In some types of pine tree, (prepositional phrase modifying the subsequent clause)
- a thick layer of needles protects the buds (layer – subject; protects – verb)
- from which new growth proceeds; (clause with subject ‘growth’ and verb ‘proceeds’. This clause modifies “buds”. What kinds of buds? New growth proceeds from these buds. Such kind of buds)
- consequently they are able to withstand forest fires relatively well. (Second independent clause joined correctly with a semi-colon with the first independent clause. As a result of the previous clause, the buds can withstand forest fires quite well)
The sentence is logical. All subject-verb pairs agree in number. However, there is a pronoun ambiguity: ‘they’ can grammatically refer to ‘buds’, ‘needles’, or ‘types of pine tree’. Logically, ‘they’ should refer to ‘buds’.
However, pronoun ambiguity is not a significant error on GMAT. Therefore, we should keep option A on hold and evaluate other options to see whether there is any better option. If no better option is found, it is fine to choose an option with pronoun ambiguity.
(A) Correct. No better option found!
(B) Incorrect. For the following reasons:
- “a thick layer of needles” is a clearer expression than “a thick needle layer”. The second expression could also mean a layer comprising of only one needle.
- “where” should refer to a place. Since “buds” is not a place, the use of “where” is incorrect. OG17 explanation seems to indicate that we can never use “from where” together. However, “from where” can be used, as in the below sentences from WSJ.com, when we want “where” to refer to a place.
- Some of its products have warranties that are specific to the country from where they were originally purchased
- The Gorkha region, from where the Gurkhas get their name, was one of the worst affected by the 2015 earthquakes
- In this option, “so that” has been used in the sense “with the result that”. Even though “so that” can be used to mean “with the result that”, such use is quite uncommon. Even though the use is not an error here, we need to be careful with such ‘uncommon’ usages on GMAT and prefer less such kind of options since they are easier to misinterpret.
(C) Incorrect. For the following reasons:
- The plural verb “protect” doesn’t agree with the singular subject “layer”.
- The adverbial phrase “relatively well” should have been placed after the direct object “forest fires” for better clarity.
(D) Incorrect. For the following reasons:
- The use of “since”, “consequently”, and “therefore” together is OVERLY redundant.
- “thick layer of needles” is preferred over “thick needle layer”, as explained in option B.
(E) Incorrect. For the following reasons:
- Error no. 2 of option B
- The use of “as a result” is redundant since the causality is already expressed through the use of “because”.