Many rare or endangered plant species are sources of drugs

Question

Many rare or endangered plant species are sources of drugs and chemicals that have proven to be useful in medicine and in agriculture. It is likely, therefore, that many plants that are now extinct would have served as the source of useful drugs and chemicals as well. Thus, if we want to ensure that drugs and chemicals from plants are available in the future, we must make every effort to preserve these precious natural resources.

Which of the following is an assumption on which the above argument depends?

A. Only rare or endangered plant species have proven to be useful as sources of drugs and chemicals.
B. Extinct plant species would have provided useful drugs and chemicals.
C. Efforts are not now being made to preserve plant species.
D. Using plants as a source of drugs and chemicals will not threaten their survival.
E. All plant species are sources of useful drugs and chemicals.

ElninoEffect · Answer

Many rare or endangered plant species are sources of drugs and chemicals that have proven to be useful in medicine and in agriculture. It is likely, therefore, that many plants that are now extinct would have served as the source of useful drugs and chemicals as well. Thus, if we want to ensure that drugs and chemicals from plants are available in the future, we must make every effort to preserve these precious natural resources.

Which of the following is an assumption on which the above argument depends?

A. Only rare or endangered plant species have proven to be useful as sources of drugs and chemicals.
 Even though other plants species may also have proven useful but we are concerned about only rare and endangered species. So negating (negation test) this statement doesn't break our conclusion. It's out. 
B. Extinct plant species would have provided useful drugs and chemicals.
 Already stated in the passage. (Assumption is something which is not stated in the passage) 
C. Efforts are not now being made to preserve plant species.
 Irrelevant. 
D. Using plants as a source of drugs and chemicals will not threaten their survival.
 Yes, because if it does then the conclusion will fail. 
E. All plant species are sources of useful drugs and chemicals.
 We are concerned about endangered and rare plant species.

Raman109 · Answer

Understanding the argument - 
Many rare or endangered plant species are sources of drugs and chemicals that have proven to be useful in medicine and in agriculture. - Fact/Background. 
It is likely, therefore, that many plants that are now extinct would have served as the source of useful drugs and chemicals as well. - Intermediate conclusion. 
Thus, if we want to ensure that drugs and chemicals from plants are available in the future, we must make every effort to preserve these precious natural resources. - Conclusion. It's conditional, meaning "preserving these precious natural resources is a "minimum condition" to ensure that drugs and chemicals from plants are available in the future."

Option Elimination - Assumption or missing premise or minimum condition.

A. Only rare or endangered plant species have proven to be useful as sources of drugs and chemicals. - Out of scope.

B. Extinct plant species would have provided useful drugs and chemicals. - Paraphrase of the 2nd statement. The assumptions are the missing premise and are not the same as stating the argument's premise. Distortion.

C. Efforts are not now being made to preserve plant species. - What is happening is out of scope.

D. Using plants as a source of drugs and chemicals will not threaten their survival. - negated option - "Using plants as a source of drugs and chemicals will threaten their survival." The minimum condition that "we must make every effort to preserve these precious natural resources" becomes less effective.

Let me give an analogy here.
Imagine a forest conservation program aimed at preserving rare species of trees known for their high-quality timber, essential for construction purposes. The program emphasizes preserving these trees to ensure a sustainable timber supply for future construction projects.

But what is the key assumption here - Harvesting timber from these trees will not threaten their survival. Because if it does, then even if we preserve the trees, future supply will not be ensured.

Another analogy - say we preserve 100 liters of rare liquid for future scientific experiments. But suppose we learned that one experiment consumes 99 liters of rare liquid, so we can't ensure availability for future experiments. So, we need to assume that the future experiments don't deplete the supply of 100 liters.

E. All plant species are sources of useful drugs and chemicals. - need not to be true.

Noida · Answer

Negating A says that Other plans may be useful.

This does not break the original argument. Instead, it supports the original argument by saying that we need to preserve plans as they may be useful. Also, here, we are concerned with plants and not rare or exotic plants.

Negating D says that using plants can lead to extinction. This breaks the argument.

thisischelso · Answer

Many rare or endangered plant species are sources of drugs and chemicals that have proven to be useful in medicine and in agriculture. It is likely, therefore, that many plants that are now extinct would have served as the source of useful drugs and chemicals as well. Thus, if we want to ensure that drugs and chemicals from plants are available in the future, we must make every effort to preserve these precious natural resources.

Which of the following is an assumption on which the above argument depends?

A. Only rare or endangered plant species have proven to be useful as sources of drugs and chemicals.
B. Extinct plant species would have provided useful drugs and chemicals.
C. Efforts are not now being made to preserve plant species.
D. Using plants as a source of drugs and chemicals will not threaten their survival.
E. All plant species are sources of useful drugs and chemicals.

Rare plants have been used in medicine. Extinct plants could have been useful
Conclusion: We should preserve the plants to make them available in the future

A not necessarily true. "Only" is too extreme there 
B Could be true but this is not a required piece of evidence to justify the argument 
C Does not need to be true. We don't need to understand the actual efforts in order to argue that preserving plants should be recommended. 
 D Yep! If using plants as medicine threatens their survival, we probably wouldn't be able to use them as medicine for long.  
E Not relevant, too broad of a statement

iamjatinagrawal · Answer

The focus of the argument is on putting efforts to preserve these natural resources so that  W   e can ensure that drugs and chemicals from plants are available in the future.

A. Only rare or endangered plant species have proven to be useful as sources of drugs and chemicals.  - doesn't concern the survival of these natural resources,  ELIMINATE  
  
B. Extinct plant species would have provided useful drugs and chemicals.  - We are not concerned with the extinct plant species,  ELIMINATE. 
 
  C. Efforts are not now being made to preserve plant species.  - This might or might not be true as we are given in the argument that every effort must be made in order to preserve these plant species but nowhere mentioned that currently no efforts are being made. But this might tempt a little at first, so you might keep this and evaluate other answer choices as well before eliminating this as the correct answer choice.

E. All plant species are sources of useful drugs and chemicals.  - We are just concerned about the survival of the plant species mentioned in the argument, not concerned with whether all species of plants and animals are sources of useful drugs and chemicals. Hence,  ELIMINATE.

D. Using plants as a source of drugs and chemicals will not threaten their survival.  - Now, this answer choice rules out the possibility that using these endangered plant species won't threaten their survival. Hence, we are free to use them given that we are making sure that every effort to preserve them is being taken care of.

I hope, now it's clear that,  Option (D)  is the right answer.

mkeshri185 · Answer

I did not get your explanation.
It is clearly written in the passage that we 'MUST' make effort to save these species. Means author is assuming we dont have any other source from which we can derive these chemicals. And A says exactly that.

If there are other sources from which we can get the chemicals then 'MUST saving these species' will fall apart.
Please tell me where i am wrong

Sajjad1994 · Answer

Explanation

Premises:

Many rare/endangered plant species are sources of useful drugs/chemicals. 
 Many extinct plants would likely have been sources of useful drugs/chemicals too. 
 Therefore, to ensure availability of such drugs/chemicals in the future, we must preserve these natural resources.

From  “many rare/endangered plants are useful”  and  “many extinct plants would have been useful”  it means  “we must preserve plants to ensure future availability.”

The gap:  The conclusion is about ensuring availability in the future. That assumes that the only or necessary way to ensure availability is preservation - but also that the plants we preserve will be the ones providing these drugs/chemicals.

A  is too extreme and not necessary. The argument doesn’t require that only rare/endangered ones are useful; it says many rare/endangered ones are useful, and many extinct ones would have been useful, so to ensure availability, preserve them. Common plants could also be useful, but the argument doesn’t depend on them not being useful. So  A  is not necessary.

B  is stated explicitly in the argument (“It is likely, therefore, that many plants that are now extinct would have served as the source of useful drugs and chemicals as well”), so it’s  not an unstated assumption.

C:  Not necessary. Even if efforts are being made now, the argument says we must make every effort — that doesn’t assume no current efforts.

D.  If using them as sources would threaten their survival, then using them conflicts with preservation. The argument assumes that using them for drugs/chemicals is compatible with preserving them. Otherwise, the goal of  “ensuring availability in the future”  via preservation is undermined if exploitation kills them off. So  D  looks necessary.

E  is far too strong and not necessary for the argument. The argument only needs that many rare/endangered ones are, and many extinct ones would have been- not all.

Answer: D

Many rare or endangered plant species are sources of drugs

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Many rare or endangered plant species are sources of drugs

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