Less detrimental than the effects of bacterial transformation
is the effects of bacterial deterioration: spoilage of food, metals corroding, decay of wood, and other undesirable alterations of substances.
Meaning: Bacterial deterioration has more detrimental effects than bacterial transformation. A list of the bacterial deterioration effects is stated.
Sentence Structure: Less detrimental than
(Comparison marker - so we can expect a comparison as we read on)the effects of bacterial transformation is
(Element 1 of comparison)the effects of bacterial deterioration
(Element 2 of comparison): spoilage of food, metals corroding, decay of wood, and other undesirable alterations of substances.
(List of the effects is stated)Quote:
(A) is the effects of bacterial deterioration: spoilage of food, metals corroding
The connecting verb "is" is incorrect as we need a plural verb. Why? Because the subject "effects of bacterial deterioration" is plural.
To understand this better let us invert this sentence: "the effects of bacterial deterioration
are less detrimental than the effects of bacterial transformation"
Also notice the parallelism error. "metals corroding" is not parallel, i.e. it does not follow the same structure, with the other elements of the list. Hence for these two reasons, (A) can be eliminated.
Quote:
(B) are the effects of bacterial deterioration: spoilage of food, metals corroding
So now we have an "are" and that rectifies the SV error. However, we still have the parallelism error as is with (A). Hence choice (B) can be eliminated
Quote:
(C) is the effects of bacterial deterioration, which include spoilage of food, metals corroding
All the errors of (A) are repeated in this choice. We also notice that the colon (:) is replaced with a ",which" so now we got to ask ourselves what does this ",which" modify? Based on this sentence structure it seems as if ",which" modifies "effects". So the verb after "which" has to be plural. Since "include" is plural we are good to go.
Why does ",which" modify "effects" and not "deterioration"? Because the list provided mentions the "effects" of deterioration. In other words, the list is mentioned to talk more about the EFFECTS of deterioration. Also, from a grammar stand point "of bacterial deterioration" is a preposition phrase modifying "effects" so... ",which" can jump over this pp to modify "effects"
Quote:
(D) are the effects of bacterial deterioration, which includes spoilage of food, corrosion of metals
Notice that all the errors of (A) are rectified. However, we now have a new SV error. Notice that which is followed by a singular verb "includes" and as discussed earlier we need a plural verb after "which". Hence option (D) can be eliminated.
Quote:
(E) are the effects of bacterial deterioration: spoilage of food, corrosion of metals
Perfect! All the errors have been rectified and no new error is introduced.
Correct Choice: (E)