Q20

[hyewonkim89]

Is (D) the answer because the prevailing view states parasites and host develop a coexistence by not harming the host?

Will someone kindly help me eliminate the other answer choices?

Thanks in advance!

[rinagoldfield]

This is an Identification question, so let’s go back to the text before looking at the answer choices. The passage states that the prevailing view of host-parasite relations is that the "host and parasite ultimately develop a benign coexistence." The passage adds that "this view is based on the idea that parasites that do not harm their hosts have the best chance for long-term survival" (lines 6-9).

In other words: Healthy hosts make for healthy pathogens!

(D) is supported. The prevailing view suggests that pathogens and hosts can BOTH thrive as they develop "a benign coexistence" with one another.

(A) is contradicted. The prevailing view says the host is NOT harmed enough to prevent the parasite from thriving.
(B) is contradicted"”that’s the author’s view, not the prevailing view.
(C) is contradicted"”that’s an example of the modification of the "prevailing view."
(E) is reversed logic. The prevailing view says "parasite thrive --> host must be thriving." This answer choice says "host thrive --> parasite must be thriving."

--Rina

[LizS111]

hey there,

I picked E because i thought the logic matched and I still dont see the reversal. The passage says, "this view is based on the idea that parasites that do not harm their hosts have the best chance for long term survival: they thrive because their hosts thrive."

in that vein i diagrammed it as such:

"they thrive because their hosts thrive" = hosts thrive --> parasites thrive
or
"parasites that do not harm their hosts have the best chance for long term survival" = parasite does not kill host --> best chance for long term survival

please advise where I am mistaken

[Laura Damone]

This is a murky area of the diagramming world because these aren't explicitly conditional claims. As such, we don't have a formula to apply and have to instead rely on our understanding of the relationships presented.

If it's true that the parasites thrive because the host is thriving, we can infer that without the host thriving, the parasite wouldn't thrive. Thus, the thriving parasite depends on the thriving host: Parasite thrive --> Host thrive.

When I'm trying to translate a statement like this into conditional notation, I'll frequently think more about what's necessary than what's sufficient. I'll ask myself questions like "which one of these two things is necessary in order to have the other."

Hope this helps!