Self-study
Creating a database of all the plant species in the scientific record has proved to be no easy task. ███ ██████████ █████████ ████ ████ ██████████ ███ ██████ ██████ ███████ █████████ ████ ████ ████ ██ ████ ███████ ██████ ███ ██ █████ ███ █████████ █████████ ████ █████ ████ █████████ ██ ██████ ████ ███████ ██ ██████ ██ ███ ████ ███████ ████████ ██████ ██ █████████ ████████
Argument Summary
The stimulus starts with a general claim: it has been difficult to create a database of all the plant species in the scientific record. We are then given two reasons for why this task is so difficult. First, botanists have for a long time been collecting and naming plants without realizing that many had already been named. In other words, many plants have been given more than one name. Second, DNA analysis has revealed that many plant varieties previously thought to be the same species are actually different species. In other words, some plant varieties that should have different names, because they are actually different species, have until now been classified under the same name.
Notable Inferences
There isn't much of an argument structure here, and there aren't many actual inferences to make. The stimulus makes a general descriptive claim — it's difficult to make a database of all known plant species — and then explains two factors contributing to this situation. While we could point to some very basic, and almost redundant, assumptions — for instance, that the DNA analysis used by the botanists is reliable — given that the question stem asks for which claim can be "most justifiably" rejected, it's better to treat this like a reverse Most Strongly Supported question. We can check each answer choice and look for the one that clearly has evidence against it from the stimulus.
10.
Of the following claims, which ███ ███ ████ ███████████ ██ ████████ ██ ███ █████ ██ ███ ██████████ ██████
a
Most of the ██████████ ███ █████████ █████ █████ █████ ██ ███ ██████████ ██████ ████ ███ ██ ██ ███████ ███
This could be true. The stimulus certainly gives us reason to think that there are many duplicates and omissions in the record, and doesn't tell us how many of these have been corrected. So we have no reason to reject the idea that most of them still need to be cleared up.
b
An accurate database ██ ███ ███ █████ ███████ ██ ███ ██████████ ██████ ███ █████ ██ ██ ███ ██ █████████ ██ █████ █████
This could be true. The stimulus doesn't tell us what benefits, if any, would come from having an accurate database, but it seems likely that such a thing would be useful. At the very least, we have no reason to reject the idea that an accurate database would help botanists in their work.
c
Duplicates and omissions ██ ███ ██████████ ██████ ████ █████ ██ ██████ █████ ████ ███████
This could be true. The stimulus doesn't say anything about other fields, or claim that such errors are unique to botany.
d
Botanists have no ██████████ ███ ███████████ ███████ ████████ █████ ███████ ████ ████ █████ ████████ ██████
This has to be false. The stimulus tells us that DNA analysis is a technique that has been used to show that distinct plant species have not been given distinct names, because they were previously thought to be the same species. So we know at least one such technique exists, and therefore this answer choice cannot be true.
e
A person who ████████ ███ ██████████ ██████ ███████ █████ ████ ███ ██ █ ███████ █████ ███ ████ █████████ ███████████ █████ ████ ██████
This could be true. The stimulus has told us that some plants have been given more than one name, and it seems plausible that catalogue entries under each of those names might contain different information. The stimulus at least gives us no reason to reject this idea.