Evidence that a giant meteorite collided with the Earth some 65 millio

OFFICIAL EXPLANATION



• HIGHLIGHTS

• has been inferred in the non-underlined portion of the sentence raises the most important logical issue: what has been inferred from the discovery of iridium?
-- to infer means to make an educated or informed guess based on available information.
-- From the man's stack of books on his table at the cafe, I inferred that he and I might have an interesting conversation.
(I have read the books or I know the subject matter contained in the books.)
-- when we infer, we draw a tentative conclusion based on facts

• Option E contains an interesting subject called a noun clause (or nominal clause, or substantive clause).

• the big question: must comma + __ED modify only the immediately preceding noun phrase, or can that modifier also modify something else?
-- blamed is an ___ED modifier in this sentence (a verbED, a past participle)
-- that is, blamed is not a verb (is not the past tense of to blame)
-- different test prep companies answer differently. I list the positions of four major companies below. I give you the resources to read about the different positions.
• the big answer? Avoid this issue if you can.

THE PROMPT



THE OPTIONS


• evidence cannot be inferred.
-- Evidence is a real thing, not an educated guess. Evidence consists of things such as facts, documents, objects, and information.
-- we cannot infer something that already exists
-- in fact, we infer something FROM the evidence
• blamed?
-- suppose that blamed refers to 65 million years ago or perhaps to Earth some 65 million years ago.
Ridiculous. Neither Earth nor a time in the past is to blame for the extinction of the dinosaurs.

• blamed, part 2
-- I suspect that blamed can modify the subject of the preceding clause, but until I find an official question to back me up, I cannot be sure.
-- suppose that blamed refers to evidence. Nonsense! Evidence did not cause the extinction and thus cannot be blamed for it.
Eliminate A


• This sentence makes sense.
• The collision (of a meteorite with the Earth a long time ago) has been inferred from the discovery of iridium. (Remove the modifier set off by commas, "an event...")
-- Logical. We may not know what iridium is. But if two celestial bodies crash, the surfaces of both are almost certainly affected.
Iridium is not normally found in an even layer; is not normally found in the earth's crust; or is not normally found at all on Earth (the iridium came from the meteor).
-- We can infer a crash (collision) between earth and a meteorite from the unusual presence of iridium.

• blamed? Modifies event. __ED modifiers that are not preceded by a comma modify the immediately preceding noun.
-- An event refers to the collision (between meteorite and Earth)
-- Could the event/collision be blamed for the extinction of the dinosaurs? Logically, yes.
Suppose we knew nothing about this theory. At the least we can say that a collision = big change = possible to blame the collision for dinosaur extinction
KEEP B. Because the answer is good, if need be, compare the other options to B!


• blamed? evidence cannot be blamed for the extinction of the dinosaurs. Evidence is information.
• has been inferred? okay. The event (the collision) has been inferred from the unusual presence of iridium.
• Option C is not a comma splice or run-on. (Option C does not impermissibly "stick" two independent clauses together with nothing more than a comma.
-- An event that is a noun that restates the event mentioned just before the comma: a giant meteorite collided with the Earth.
-- when we have a clause without a noun and we need a noun, we can use a few words to encapsulate what the clause means.
-- those few words in this case are a "summative modifier"—a word or group of words that summarizes the preceding clause.
-- whatever you want to call it, an event is a noun modifier (an appositive) that modifies colliision
Eliminate C


• has been inferred? No. The meteor itself was not inferred. The collision between meteor and Earth was inferred from the unusual presence of iridium.
-- we know that the intended meaning is probably the collision has been inferred because of the other options and especially because of (B).
-- I think that we can also reject this option's logic in isolation:
we cannot infer a celestial body itself. (How do you "guess" a meteorite?) We can infer the presence of a celestial body.
• whose both can and must be used for things and people.
-- whose is the possessive form of both who (people) and which (things)
-- whose is the only word available. See this article, here.
-- I think that some of you got confused with the possessive pronoun its.
No worries. This is the place to work through the issues.
-- see further analysis below
Eliminate D


• Above all: this sentence is not as good as B
• That there was a collision of a giant meteorite with the Earth some 65 million years ago is the subject of the sentence. No kidding.
-- That whole clause is called a noun clause (or nominal or substantive clause).
-- Although the noun clause has a subject and a verb, the clause is a noun and can do anything a "regular" noun can do. More on this structure below.
• whether this sentence is grammatical [noun clause just then!] depends on how we interpret blamed, but even if the sentence is grammatical, (E) is not as good as (B).
-- some of you noted that "an event" would make this answer grammatical.
You are correct. Well done. An event would refer to the collision, and the collision is what gets blamed for extinction.
-- we don't have "an event." Let's try both cases.

• Case #1: the sentence is grammatical because blamed modifies collision
-- in that case the sentence is grammatical because the subject, collision, and the verb, has been inferred, are not interrupted by a nonsensical modifier
-- Noun clauses beginning with THAT mean The fact that

-- the sentence is also logical: The fact that there was a collision between a meteorite and the Earth . . . has been inferred from the unusual presence of iridium.

Case 1 conclusion: Option E is both grammatical and logical, but not as good an answer as B. Eliminate E.
Option E is not as clear, concise, or easy to understand as B.
-- "That there was" are unnecessary words.
-- there was (in which there is kind of a "dummy" placeholder) is uncommon on the GMAT in this kind of situation. ("There was" is fairly uncommon anyway.)
-- do not dismiss noun clauses automatically, though. Correct official answers use them.

Case #2: Option E is not grammatical because blamed modifies years or Earth
Although the subject (That there was a collision...) and the verb (has been inferred) are still correctly paired, we cannot just dismiss an erroneous or misplaced modifier.

The collision was blamed, not years and not the Earth.
Case 2, conclusion: Option E is fairly logical but a modifier error makes it ungrammatical. Eliminate E.
-- what is blamed for the extinction of the dinosaurs? This fact: "a giant meteorite collided with the Earth."
-- stated differently, a collision (noun taken from collided) between a meteorite and the Earth is blamed for the extinction of the dinosaurs
Eliminate E

The answer is B

• Issues

• comma + __ ED = blamed = past participle
-- past participles (verbED words) without a comma always modify the immediately preceding noun
-- what can [comma + __ED] modify?

Mike McGarry, Magoosh -- usually modifies a nearby noun, can modify a faraway noun. Depends on context:
the ability of a past participle verb to modify a distant noun depends on context.
See this blog comment attached to the article Participle Phrases on the GMAT, here

Ron Purewal, formerly of Manhattan Prep: can modify both the preceding noun and the subject of the previous clause, here

Vertias Prep: can modify a far away noun, but GMAC is not "keen" on that situation, so "avoid it." HERE

egmat: only the preceding noun or preceding main noun in a noun phrase: HERE. (based on an official explanation from OG 12)

My position is similar to those of the first three sources listed.

In this question, we do not have to address blamed to eliminate the four incorrect answers.

• WHOSE
-- is the possessive form of who and which
-- is used for both people and things because it's the only word available
-- is confusing because it contains the word who but not the word which
-- should not be confused with who's, which means who is

true: who's = who is = only for people
true: the thing that upsets me = that is used only for things, never for people
true: the person who upsets me = who is used only for people, never for things
true: the person whose behavior upsets me = the person who is behaving in a way that upsets me
true: the task whose demands are unreasonable = the task includes (has) demands that are unreasonable

• Noun clauses - for more on noun (substantive, nominal) clauses, see Substantive Clauses on the GMAT, here.

COMMENTS

Shishou and joohwangie , welcome to SC Butler.

I am really impressed by nearly all of these answers.
I see incisive analysis—people are thinking about grammar, logic, and meaning. Boom. (Spot on.)

Answers with explanations get kudos. Very nicely done.