Yeasts capable of leavening bread are widespread, and in the many cent

Question

Yeasts capable of leavening bread are widespread, and in the many centuries during which the ancient Egyptians made only unleavened bread, such yeasts must frequently have been mixed into bread doughs accidentally. The Egyptians, however, did not discover leavened bread until about 3000 B. C. That discovery roughly coincided with the introduction of a wheat variety that was preferable to previous varieties because its edible kernel could be removed from the husk without first toasting the grain.

Which of the following, if true, provides the strongest evidence that the two developments were causally related?

(A) Even after the ancient Egyptians discovered leavened bread and the techniques for reliably producing it were well known, unleavened bread continued to be widely consumed.

(B) Only when the Egyptians stopped the practice of toasting grain were their stone-lined grain-toasting pits available for baking bread.

(C) Heating a wheat kernel destroys its gluten, a protein that must be present in order for yeast to leaven bread dough.

(D) The new variety of wheat, which had a more delicate flavor because it was not toasted, was reserved for the consumption of high officials when it first began to be grown.

(E) Because the husk of the new variety of wheat was more easily removed, flour made from it required less effort to produce.

Source : GMAT Paper Set 19
Source : GMATPrep Default Exam Pack

CrackverbalGMAT · Accepted Answer

Yeasts capable of leavening bread are widespread, and in the many centuries during which the ancient Egyptians made only unleavened bread, such yeasts must frequently have been mixed into bread doughs accidentally. The Egyptians, however, did not discover leavened bread until about 3000 B. C. That discovery roughly coincided with the introduction of a wheat variety that was preferable to previous varieties because its edible kernel could be removed from the husk without first toasting the grain.

Which of the following, if true, provides the strongest evidence that the two developments were causally related?

Step 1 of any critical reasoning question is to simplify and understand the data being presented to us. When the information is clearly mapped out, the pattern becomes more obvious to us.

Attachment:

wheat.jpg [ 39.51 KiB | Viewed 37264 times ]

Of course, you can’t do all this in the exam, but you get the drift…

Simply put, we have to look for an option that tells us that the discovery of leavened bread and the introduction of a new variety of wheat that does not need fire roasted have a causal relationship. Anything that does not indicate a causal relationship is out!

Let’s check out the options…

(A) Even after the ancient Egyptians discovered leavened bread and the techniques for reliably producing it were well known, unleavened bread continued to be widely consumed.

Nice to know! I personally love unleavened bread so I understand the popularity. But does this show me that the two facts mentioned in the argument have a causal relationship? No. Eliminate!

(B) Only when the Egyptians stopped the practice of toasting grain were their stone-lined grain-toasting pits available for baking bread.

This option tells me that the stone-lined grain-toasting pits were finally available. But this gives me no indication of a causal relationship between the two facts mentioned in the argument. Eliminate!

(C) Heating a wheat kernel destroys its gluten, a protein that must be present in order for yeast to leaven bread dough.

The first reaction that may come to mind is, “So?!”

But think about it…when you heat a wheat kernel, the gluten is destroyed. Gluten is needed for the yeast to leaven bread dough. The argument says that yeast capable of leavening bread was widespread and must frequently have been mixed into bread doughs accidentally. But even if that were the case, there’s no gluten. Which means the bread couldn’t get leavened, even though the yeast needed was present.

Fast forward to 3,000 B.C. A new variety of wheat is introduced that does not need roasting. This means the gluten says intact and is available to the yeasts. The bread dough gets leavened. Ta-daaaa!

This option shows us that there was indeed a causal relationship between these two facts. Select!

(D) The new variety of wheat, which had a more delicate flavor because it was not toasted, was reserved for the consumption of high officials when it first began to be grown.

The only thing that this option tells us is that this kind of discrimination goes back centuries

! Eliminate!

(E) Because the husk of the new variety of wheat was more easily removed, flour made from it required less effort to produce.

This might be a fact, but it doesn’t shows us that there was a causal relationship between the two facts mentioned in the argument. Out you go!

- Nitha Jay
GMAT Verbal SME

! Eliminate! (E) Because the husk of the new variety of wheat was more easily removed, flour made from it required less effort to produce. This might be a fact, but it doesn’t shows us that there was a causal relationship between the two facts mentioned in the argument. Out you go! - Nitha Jay GMAT Verbal SME

AnishPassi · Answer

The Story

Yeasts capable of leavening bread are widespread, 
Yeasts that can make bread fluffy are common.

and in the many centuries during which the ancient Egyptians made only unleavened bread, such yeasts must frequently have been mixed into bread doughs accidentally.

For many centuries ancient Egyptians made only non-fluffy bread.

During those times, such yeasts must have been added into bread doughs accidentally. 
“must … have been” indicates that this is a speculation.

How come the author is speculating that such yeasts must frequently have been mixed into bread doughs?
Perhaps because such yeasts are widespread.

Why “accidentally”?
Not certain where the author got this from. Perhaps because the Egyptians made only unleavened bread for many centuries. So maybe ingredients capable of leavening bread were added accidentally. This reasoning could explain the use of the word ‘accidentally’, but I am open to other interpretations as I continue too

How come the bread was unleavened even though yeasts capable of leavening bread were frequently mixed into bread doughs, albeit accidentally?Perhaps something in the baking process caused the yeasts to not make the bread rise. (I understood this idea by relating this portion with the initial part: the phrase ‘yeasts capable of leavening bread’. These yeasts are “ capable of leavening bread ”. That doesn’t mean that if they are added, bread will rise for sure.)

The Egyptians, however, did not discover leavened bread until about 3000 B. C. 
Although yeasts would have been accidentally mixed for quite a while, leavened bread was only discovered later (3000 B. C.). So bread only started rising in around 3000 BC (much later, I presume) for the Egyptians.

That discovery roughly coincided with the introduction of a wheat variety that was preferable to previous varieties because its edible kernel could be removed from the husk without first toasting the grain. 
“That discovery” – what discovery? The discovery of fluffy bread
Around the same time that fluffy bread was discovered (3000 BC), a type of wheat was introduced. ( Why are they talking about wheat? Ah! The main ingredient of bread. )

This type of wheat was preferable to previous types. We’re given a reason for the preference – because the non-edible part (husk) of the grain could be separated without first toasting.(‘ edible kernel could be removed from the husk’ —> the husk was probably the non-edible part )

Gist:  
1. Certain yeasts help make bread fluffy.
2. Such yeasts are very common.
3. Even though such yeasts must have been accidentally added to bread doughs, for many centuries bread didn’t rise.
4. The Egyptians started using a new variety of wheat. 
5. This one did not require toasting of the grain.
6. X`Around the same time that the Egyptians started using this new variety of wheat, they discovered fluffy bread

Question Stem

Which of the following, if true, provides the strongest evidence that the two developments were causally related?

What ‘two developments’?

1. Discovery of leavened bread,
2. Introduction of the new variety of wheat.

“the two developments were causally related”

So,

Either 1 caused 2 
  Or, 2 caused 1

Do both these causal relations make equal sense?

The discovery of fluffy bread caused the introduction of new wheat 
 The introduction of the new wheat caused the discovery of fluffy bread

The first relation does not make sense; the latter one does. Right?

Framework:  So, after reading the correct answer, I should believe more than I currently do in the notion that the Egyptians discovered fluffy bread because they had started using the new variety of wheat.

Perhaps the fact that the new wheat variety did not need to be toasted somehow led to the discovery.

Let’s see.

Answer Choice Analysis

(A) Even after the ancient Egyptians discovered leavened bread and the techniques for reliably producing it were well known, unleavened bread continued to be widely consumed. 
  Incorrect.    
Our job is to look for something that indicates a causal relation between the discovery of leavened bread and the introduction of the new wheat.
This option simply tells us that unleavened bread continued to be popular even after awareness about leavened bread had spread.
It does not help us establish the required causal relation. Irrelevant.

(B) Only when the Egyptians stopped the practice of toasting grain were their stone-lined grain-toasting pits available for baking bread. 
  Incorrect.    
These “stone-lined grain-toasting pits” became available for baking only when they stopped toasting the grain. So, only after they started using the new variety of wheat.

So, earlier the Egyptians must have used some other pits, or some other form of an oven to bake bread.

This answer choice only talks about a new source of baking becoming available. It does not mention anything about whether this new source had anything to do with the bread becoming fluffy. So, this one is not helpful to establish the causal relation.

Now, what if the answer choice were:

(B’) Stone-lined grain-toasting pits became available for baking bread only after the Egyptians stopped the practice of toasting grain, and bread baked in these pits leavened.

This answer choice would have been correct.
 
1. Introduction of the new wheat would have led to stone-lined grain-toasting pits becoming available for breaking bread
2. Using these pits would have led to bread leavening
3. That’s how the Egyptians would have discovered leavened bread
4. So, introduction of the new wheat would have led to the discovery of leavened bread

The original one, however, does not tell us whether the kind of pit in which bread was baked was related to bread becoming fluffy.

(C) Heating a wheat kernel destroys its gluten, a protein that must be present in order for yeast to leaven bread dough. 
  Correct.   
“a protein that  must be present  for yeast to leaven bread dough.” So, If the protein is not present, the bread will not leaven even if yeast is added.

How is “heating a kernel” relevant?

Oh, the new wheat variety did not require toasting (a form of heating); the old ones did.

The older varieties of wheat had to be heated initially. That would have destroyed their gluten. And that’s why bread wouldn’t have risen, even if there was yeast in the dough.

Now that the grain was not initially toasted, the protein would have remained in the wheat. And perhaps the gluten and the “accidental” yeast would have made the bread rise, leading to the discovery of leavened bread.

This answer choice does give me evidence that using the new variety of wheat led to the discovery of fluffy bread.

(D) The new variety of wheat, which had a more delicate flavor because it was not toasted, was reserved for the consumption of high officials when it first began to be grown. 
  Incorrect.    
Who consumed this wheat does not help us establish a causal relation between the introduction of the wheat and the discovery of leavened bread. Irrelevant.

(E) Because the husk of the new variety of wheat was more easily removed, flour made from it required less effort to produce. 
  Incorrect.    
Ok, but did the new wheat lead to the discovery of fluffy bread? All we learn is that flour from the new wheat required less effort to produce. We do not learn anything about how the Egyptians discovered fluffy bread. Irrelevant.

Additional Notes

Whenever presented with a contrast word: however, but, etc, it is our job to understand what the contrast is. It is not enough to just acknowledge that there is a contrast.
In this passage, when we relate the second statement with the first, we realise that 3000 BC would have to be a time (much?) later than when they used to make only unleavened bread.
 
 I have labelled the question as a ‘Strengthen’ question on top. One way to look at the question is that the conclusion is in the question stem (The two events are causally related), and our job is to find evidence to support this. However, remember, at the end of the day, our job is to answer the question that’s been asked on the screen. It doesn’t matter whether we can fit the question into a category. In fact, if you find that by categorising a question you might lose some nuance, it’s better not to categorise.

smartmanav · Answer

Y C is correct ? Can someone explain with proper convincing points plz ?

fozzzy · Answer

What's the difficulty level for this question? I couldn't figure out what question stem it was?

KyleWiddison · Answer

Tough to peg a difficulty level on questions. This one is tricky but manageable when you understand the question.

Understanding the question type is tricky because the question includes logical words (causal) that don't tie to a question type. The type is actually 'strengthen the conclusion' but the conclusion can be hard to find because its hidden in the question. The conclusion is that there is a causal relationship between the introduction of the non-toasted wheat and bread leavening.

I'll review the options when I get back to a computer.

KW

Posted from my mobile device

KyleWiddison · Answer

As I mentioned in my prior post, this question is asking you to strengthen the conclusion that the discovery of leavend bread was causally related to the introduction of the non-toasted wheat. Your answer needs to make a definitive connection between those two events.

A - Makes no connection between non-toasted wheat and leaven.
B - We are trying to connect non-toasting and leavening...the baking process after the fact is not relevant.
C - This answer perfectly connects the non-toasting with the leavening. Before, when wheat was toasted, the gluten was destroyed, preventing the bread from leavining. With the new, non-toasted wheat, the gluten is present and the leavening process can take place.
D - This answer does not connect non-toasting with leaven.
E - Again, no connection made between non-toasting and leaven.

KW

Yeasts capable of leavening bread are widespread, and in the many centuries
during which the ancient Egyptians made only unleavened bread, such yeasts must
frequently have been mixed into bread doughs accidentally. The Egyptians,
however, did not discover leavened bread until about 3000 B. C. That discovery
roughly coincided with the introduction of a wheat variety that was preferable to
previous varieties because its edible kernel could be removed from the husk
without first toasting the grain.

Which of the following, if true, provides the strongest evidence that the two
developments were causally related?
A. Even after the ancient Egyptians discovered leavened bread and the techniques
for reliably producing it were well known, unleavened bread continued to be
widely consumed. 
B. Only when the Egyptians stopped the practice grain were their stonelined
grain-toasting pits available for baking bread.
C. Heating a wheat kernel destroys its gluten, a protein that must be present in order
for yeast to leaven bread dough.
D. The new variety of wheat, which had a more delicate flavor because it was not
toasted, was reserved for the consumption of high officials when it first began
to be grown.
E. Because the husk of the new variety of wheat was more easily removed, flour
Made from it required less effort to produce.

Divad · Answer

as a non native I have no chance to understand the passage. No one knows all the important words like yeast, kernel, husk leavened dough and so on. How is it important to a MBA application test, how good my vocabulary in the field of baking is? I could not use my analytical skills because I just coudnt understand a word of that passage!? Usually I get 80% or more right in CR, but as a non native there is no chance to get this CR correct. Except you work in a multinational bakery I guess haha. Sorry for my comment but it just frustrates me.

Shrey9 · Answer

Hey, its not necessary to know such words..
just try to understand the logic of the sentence.
Some people, tried making something, but accidentally they made something else.. they didn't know about that, until and unless some other thing came up, which had specific characteristics, one of them is "without first toasting the grain." = heating

C) says, Heating  (a wheat kernel)  destroys its gluten,  (a protein that must be present in order for yeast to leaven bread dough.)

Other choices aren't that closely talking about "heating"

Also, the expert from Manhattan has told us a lot, which can help us eliminate most of the other choices, and understand this question very well

705in11112025 · Answer

knowing what is a leavened bread vs unleavened will help a lot in answering this question. Guess outside knowledge has some value after all.

NEYR0N · Answer

I'd like some help regarding A, had it been changed a little.

In my understanding, the passage sets up a contrast between the new technique (leavened bread enabled by the new wheat) and the old ways (unleavened bread). The supposed causal claim is that this contrast led Egyptians to start working with leavened bread.

Answer choice A says that even after the discovery and after it being widespread (a.k.a no more contrast), people still continued using the old way (unleavened bread). To me, that weakens the causal link, since the effect wasn't dominant.

Now here's my confusion: if A had instead said that people reverted fully to only unleavened bread ( so now there's no contrast and the effect is reverted to baseline), wouldn't that actually strengthen the causal story? My reasoning is that once the contrast disappeared, people naturally fell back to their old ways, which seems consistent with the idea that the new wheat was the key difference that enabled leavening in the first place.

GMATNinja · Answer

First, let's review the passage to make sure you're understanding it correctly. We're told that two things happened around 3000 B.C.:

1) The Egyptians finally discovered leavened bread (even though, for centuries prior, the yeasts responsible for leavening were widespread and must frequently have been mixed into bread doughs accidentally).

A new (and preferable) wheat variety was introduced (wheat that could be used without having to first toast the grain).

A new (and preferable) wheat variety was introduced (wheat that could be used without having to first toast the grain).

So, is it just a coincidence that those two things happened around the same time? Or did one cause the other?

(C) suggests that #2 caused #1. Before 3000 B.C., it seems as though the Egyptians needed to toast the grain of their wheat before using it for bread. That would have rendered leavening impossible, and that explains why the Egyptians didn't have leavened bread, even though the yeast was readily available. Once they started using the new wheat that did not require toasting, the discovery of leavened bread was inevitable.

What kind of bread the Egyptians preferred to consume after that discovery is irrelevant. Maybe they fell in love with the new stuff and stopped making/eating unleavened bread. Or maybe they thought leavened bread was gross and stuck with the familiar unleavened bread. That doesn’t change the fact that they now are ABLE to make either type. Regardless of their preference, we're left wondering WHY the Egyptians finally discovered leavened bread in the first place. That's why (A) and your altered version of (A) are irrelevant.

If instead we had something like, "A fungus killed off the new wheat 1,000 years later, and suddenly Egyptians stopped eating leavened bread entirely," then that would certainly suggest a causal connection between the new wheat and leaved bread. But simply knowing that the Egyptians preferred one or the other, even though both are available, doesn't help.

(C) is the only option that suggests that #1 and #2 above are causally linked.

egmat · Answer

This one can be tricky - you're dealing with a historical puzzle that requires you to connect two seemingly separate developments. Let me walk you through how to approach this systematically.

Understanding What We're Looking For

The passage sets up an intriguing mystery: yeast was everywhere, Egyptians accidentally mixed it into bread for centuries, yet they didn't discover leavened bread until around 3000 B.C. At that same time, a new wheat variety was introduced that  didn't need toasting  before removing the husk.

The question asks you to strengthen the causal connection between these two developments. Here's the key insight: you need more than just a timing coincidence - you need a  mechanism  that explains HOW the new wheat variety enabled the discovery of leavened bread.

Let's Think Through This Step by Step

Step 1: Identify the Puzzle 
Why didn't leavening work for centuries despite accidental yeast contact? Something must have been preventing it.

Step 2: Notice the Key Difference 
The critical change mentioned is that the old wheat required  toasting , while the new variety didn't. This processing difference must be important.

Step 3: Find the Missing Link 
We need an answer that explains:
 
 Why leavening was  impossible  with the old toasted wheat 
 Why leavening became  possible  with the new untoasted wheat

Step 4: Evaluate Answer C 
Answer C tells us that heating wheat kernels destroys gluten, and gluten  must be present  for yeast to leaven bread dough.

This is your "aha moment" - it perfectly explains the causal chain:
 
 Old wheat → toasting required → gluten destroyed → yeast can't work (even with accidental contact) 
 New wheat → no toasting needed → gluten preserved → yeast can finally work → discovery possible

This creates a direct scientific mechanism linking the wheat variety change to the leavening discovery.

Why Other Answers Don't Work

Answer B  mentions that toasting pits became available for baking, but this is just about infrastructure - it doesn't explain the scientific reason why leavening was impossible before.

Answer E  talks about ease of flour production, but efficiency doesn't explain why yeast suddenly started working after centuries of accidental contact.

The Correct Answer: C

---

Want to Master This Question Type?

Understanding the core logic is great, but there's so much more to learn about strengthen questions involving causal relationships. The complete solution on Neuron shows you the systematic framework for identifying causal mechanisms, recognizing common trap answers, and applying this pattern to similar CR questions.

You can check out the  detailed breakdown on Neuron by e-GMAT  to see how this approach applies systematically to all causal reasoning questions. You can also explore comprehensive solutions for  other GMAT official questions here  with practice quizzes and detailed analytics into your strengths and weaknesses.

Happy studying!

Yeasts capable of leavening bread are widespread, and in the many cent

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

Yeasts capable of leavening bread are widespread, and in the many cent

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards