In their native habitat, amaryllis plants go dormant when the soil in which they are growing dries out during the dry...

Annie on November 5, 2019

Hi @Lucie,

This question is asking you to find the assumption on which the argument depends. Therefore, you're looking for an answer choice that must be true for the conclusion to be correct. Here's a breakdown of the argument:

Premise: In their native habitat, amaryllis go dormant when the soil dries out during the dry season.
Conclusion: For amaryllis as house plants to thrive you should withhold water from them during part of the year so they go dormant.

Answer Choices:
(A) is incorrect: The conclusion has nothing to do with other types of plants besides the amaryllis. Therefore, there is no assumption being made about "most kinds of plants."

(B) is incorrect. Again, the conclusion does not deal with other kinds of plants. Therefore, there is no assumption being made about how difficult amaryllis are compared to other plants.

(C) is incorrect. This answer choice is just making the conclusion more detailed (aka saying water must be withheld at a specific time of year, rather than just at some point). As this is simply more specific, it is not an assumption on which the argument is based.

(D) is incorrect. The conclusion does not discuss the length of time that a plant must go dormant.

(E) is correct. The conclusion is assuming that going dormant is beneficial for all amaryllis plants, both house plants and those in the wild. This answer choice points this out. Since this is a must be true question, a good way to double check the answer is to see if the conclusion would hold if this answer choice were false. Here, if going dormant did nothing more than protect plants from death during overly dry periods, there would be no benefit to house plants going dormant as they can always be watered.