Smith’s new grazing land consists entirely of fescue grass. Half of

Question

Smith’s new grazing land consists entirely of fescue grass. Half of the grass contains a species of fungus that makes cows ill when they eat it. Smith’s cows will most likely learn to graze exclusively on the grass that does not contain the fungus, since, like many other animals, cows will avoid eating a patch of grass if they sense a substance in it that has made them ill.

Which one of the following is an assumption required by the argument?

(A) At least one other species of fungus is contained in the fescue grass that does not contain the fungus that makes cows ill.

(B) At least some cows that have been made 1ll by the fungus are capable of sensing the fungus in fescue grass.

(C) The fungus that makes cows ill cannot be found in any variety of grass other than fescue grass.

(D) The cows are the only animals grazing on the new land who become ill after eating the fungus contained in the fescue grass.

(E) The fungus that is contained in the fescue grass cannot be eradicated without destroying the
grass itself

kntombat · Answer

I think the answer is B as it is the only option that goes someway to solve the mystery as to how,  "Smith’s cows will most likely learn to graze exclusively on the grass that does not contain the fungus" .

Vibhu245 · Answer

I am unable to understand why it is given as B. Author makes an argument that cows will learn to sense fungus after falling ill because of it. Why is it an assumption that some cows have already fallen ill for that to be true? If option E is true, Cows might find an alternative method to get rid of fungus and hence the argument of author that left over case that cows graze only the land with no fungus weakens. Please explain it in detail!

TheGraceful · Answer

Happy to help. Smith’s new grazing land consists entirely of fescue grass. Half of the grass contains a species of fungus that makes cows ill when they eat it. Smith’s cows will most likely learn to graze exclusively on the grass that does not contain the fungus, since, like many other animals, cows will avoid eating a patch of grass if they sense a substance in it that has made them ill . <== Underlined portion answers your question - "Why is it an assumption that some cows have already fallen ill for that to be true?". From premise/statement highlighted above it's clear that cows will avoid the patch of grass with fungus, only after cows fall ill. Argument doesn't mention/hint that cows have any special powers/cognitive abilities to avoid grass with fungus. (behaving much like GMAT students, learning from mistakes

) The only option that closes the gap between conclusion - Cows will start avoiding patches of grass with fungus after falling ill - and premise - grass contains fungus and makes cows ill - will be assumption. Only option B is close. (A) At least one other species of fungus is contained in the fescue grass that does not contain the fungus that makes cows ill. (B) At least some cows that have been made 1ll by the fungus are capable of sensing the fungus in fescue grass. (C) The fungus that makes cows ill cannot be found in any variety of grass other than fescue grass. (D) The cows are the only animals grazing on the new land who become ill after eating the fungus contained in the fescue grass. (E) The fungus that is contained in the fescue grass cannot be eradicated without destroying the grass itself

svasan05 · Answer

Pre-thinking:

Conclusion:  Smith’s cows will most likely learn to graze exclusively on the grass that does not contain the fungus.

Premises on which it is based:  
i) Half of the Smith's fescue grass contains a species of fungus that makes cows ill when they eat it.
ii) Cows will avoid eating a patch of grass if they sense a substance in it that has made them ill.

At first glance, there does not seem to be any gap between the premise and the conclusion. However, we can observe that the premise talks about cows (in general) and an illness causing substance (in general). It is possible that this generality may not hold for Smith's cows and for this particular fungus. There really is no other gap in the conclusion. Therefore, the assumption must somehow convey that this generality will hold in the present situation as well.

Let us look at the answer options.

(A) At least one other species of fungus is contained in the fescue grass that does not contain the fungus that makes cows ill.  Other fungus species are irrelevant to the discussion at hand. Eliminate.

(B) At least some cows that have been made ill by the fungus are capable of sensing the fungus in fescue grass.  Correct answer and consistent with our pre-thinking. If no cows made ill by the fungus are capable of sensing the fungus, then the conclusion fails.

(C) The fungus that makes cows ill cannot be found in any variety of grass other than fescue grass.  Other grass varieties are irrelevant to the discussion at hand, since Smith's farm entirely consists of fescue grass. Eliminate.

(D) The cows are the only animals grazing on the new land who become ill after eating the fungus contained in the fescue grass.  Whether other animals become ill or not is not relevant since the conclusion is only about cows. Eliminate.

(E) The fungus that is contained in the fescue grass cannot be eradicated without destroying the grass itself  Since only half the grass in Smith's farm contains the fungus and the conclusion is about cows avoiding such grass, we are not interested in the eradication of the fungus. Eliminate.

Hope this helps.

Smith’s new grazing land consists entirely of fescue grass. Half of

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Smith’s new grazing land consists entirely of fescue grass. Half of

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