Hi domfrancondumas, I hope this helps.
A. makes an unwarranted assumption that a characteristic that is shared by two classes of things
is their only common feature. For this answer choice, it states, "shared by two classes of things." In this argument, there is only one class of thing
mentioned which is the orchid flower.
B. assumes without warrant that a characteristic distinguishes one class of things from another is the only characteristic characteristic that distinguishes that class from the other. This answer choice is incorrect because in this argument, we are concerned with the similarity not differences.
C. mistakes a characteristic that is unique to one particular class of things for a characteristic that is unique to an unrelated class of things. This answer choice is incorrect because the argument DOES NOT link one class of things with other class of things.
D. Treats a characteristic known to be true of one class of things as if that characteristic were unique to that class. This answer choice is correct because the argument assumes that any orchid species that are pollinated solely by insects have features that attract insects.
. Since the recently discovered orchid has this characteristic, the argument concludes that the recently discovered orchid is pollinated solely by insects.
E. makes broad generalizations about all members of a particular class of things on the basis of what is known about a member of an unrelated class of things. This answer choice is incorrect because the argument uses generalization of particular class to apply to specific thing in that class. So, this is actually reversed.
Don't be afraid to fail, but be afraid not to try