X: Since many chemicals useful for agriculture and medicine derive from rare or endangered plant species, it is likely that many plant species that are now extinct could have provided us with substances that would have been a boon to humanity. Therefore, if we want to ensure that chemicals from plants are more serious efforts to preserve for all time our natural resources.
Y: But living things are not our “resources.” Yours is a selfish approach to conservation. We should rather strive to preserve living species because they deserve to good they can do us.
What this question is testing
Your task
Find the assumption the argument requires in order for its conclusion to hold.
Common trap
Answers that would help the argument but aren't strictly required (sufficient, not necessary).
Winning move
Negate each choice — the right one breaks the argument when negated.
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