Critical Reasoning

[spoiler]In the below GPrep Q...OA = C....can someone please tell why D is wrong ?[/spoiler]

Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected whitefooted mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number
of ticks acquiring the bacterium? and hence the number of people contracting Lyme disease-would likely decline.
Which of the following, if true, most strengthens the argument?
A. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
B. There are no known cases of a human's contracting Lyme disease through contact with white-footed mice.
C. A deer tick feeds only once while in the larval stage.
D. A single host animal can be the source of bacteria for many tick larvae.
E. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

goelmohit2002 wrote:[spoiler]In the below GPrep Q...OA = C....can someone please tell why D is wrong ?[/spoiler]

Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected whitefooted mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number
of ticks acquiring the bacterium? and hence the number of people contracting Lyme disease-would likely decline.
Which of the following, if true, most strengthens the argument?
A. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
B. There are no known cases of a human's contracting Lyme disease through contact with white-footed mice.
C. A deer tick feeds only once while in the larval stage.
D. A single host animal can be the source of bacteria for many tick larvae.
E. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

Its a tricky question. I chose E. I eliminated D because Its very general.

Here's my attempt to break it down:

- Humans get Lyme disease by deer ticks
-- deer ticks pick up bacteria when 1) in larval stage and 2) feeding on whitefooted mice
--- other species that deer ticks feed on do NOT have bacteria

by inc "other species" --> dec deer acquiring bacteria --> humans dec contamination

need to strengthen!

a) don't care about ticks consequence to contracting
b) we already know Lyme disease is (only) cause by bacteria transmitted to humans by deer ticks
c) if ticks feed only once and they feed on other species, then no chance to acquiring bacteria from mice
d) This strengthens claiming bacteria can be spread multiple times (we want to reduce spread, not increase it)
e) we don't care about Other bacteria only ones that cause Lyme disease

I personally picked B but I now see that B is not valid since its the more general version of 1st sentence - that Lyme disease in caused by bacteria in ticks (ONLY)

Hope this helps
Hop

m&m wrote:Here's my attempt to break it down:

- Humans get Lyme disease by deer ticks
-- deer ticks pick up bacteria when 1) in larval stage and 2) feeding on whitefooted mice
--- other species that deer ticks feed on do NOT have bacteria

by inc "other species" --> dec deer acquiring bacteria --> humans dec contamination

need to strengthen!

a) don't care about ticks consequence to contracting
b) we already know Lyme disease is (only) cause by bacteria transmitted to humans by deer ticks
c) if ticks feed only once and they feed on other species, then no chance to acquiring bacteria from mice
d) This strengthens claiming bacteria can be spread multiple times (we want to reduce spread, not increase it)
e) we don't care about Other bacteria only ones that cause Lyme disease

I personally picked B but I now see that B is not valid since its the more general version of 1st sentence - that Lyme disease in caused by bacteria in ticks (ONLY)

Hope this helps
Hop

But IMO D actually strengthens too....as earlier they were feeding on infected food.....but they will now not eat the infected food....

For e.g. Earlier 100 deer ticks were eating say a single infected food...

But now due to more availability and less competition to food...less number of deer ticks will eat the infected food....say for example....80.....

so is it not strengthening the argument ?

Can someone please tell where is the flaw in my reasoning ?

increasing supply of other uninfected species of mice would lead to fewer deer ticks acquiring the bacteria=># of people getting Lyme decreases

D: A single host animal can be the source of bacteria for many tick larvae
=>a single white footed mice can infect many larvae- doesnt strengthen the argument. if anything it weakens the argument (m&m has mentioned): inspite of more larvae feeding on uninfected mice,there may not be any fewer larvae infected by the infected white footed mice.

scoobydooby wrote:increasing supply of other uninfected species of mice would lead to fewer deer ticks acquiring the bacteria=># of people getting Lyme decreases

D: A single host animal can be the source of bacteria for many tick larvae
=>a single white footed mice can infect many larvae- doesnt strengthen the argument. if anything it weakens the argument (m&m has mentioned): inspite of more larvae feeding on uninfected mice,there may not be any fewer larvae infected by the infected white footed mice.

Thanks Scooby,

Can you please tell what I am missing in the line of reasoning that I put above....kindly refer to the previous post that I gave with one example.

Thanks
Mohit

goelmohit2002 wrote:
But IMO D actually strengthens too....as earlier they were feeding on infected food.....but they will now not eat the infected food....

For e.g. Earlier 100 deer ticks were eating say a single infected food...

But now due to more availability and less competition to food...less number of deer ticks will eat the infected food....say for example....80.....

so is it not strengthening the argument ?

Can someone please tell where is the flaw in my reasoning ?

point in D is not fewer tick larvae feed on infected food, but that each infected food (mouse) can potentially infect many larvae

scoobydooby wrote: inspite of more larvae feeding on uninfected mice,there may not be any fewer larvae infected by the infected white footed mice.

Hi Scooby,

But the same problem I guess is with C too....

Even if we increase the number of uninfected food...deer ticks "may" not eat that uninfected food....thus even though uninfected food supply is increased..... there may not be any fewer larvae infected by the infected white footed mice.

Please note that in the argument....it is not mentioned that there is some limited supply of uninfected food....

Please tell what I am missing here.

goelmohit2002 wrote:

scoobydooby wrote: inspite of more larvae feeding on uninfected mice,there may not be any fewer larvae infected by the infected white footed mice.

Hi Scooby,

But the same problem I guess is with C too....

Even if we increase the number of uninfected food...deer ticks "may" not eat that uninfected food....thus even though uninfected food supply is increased..... there may not be any fewer larvae infected by the infected white footed mice.

Please note that in the argument....it is not mentioned that there is some limited supply of uninfected food....

Please tell what I am missing here.

the passage says if uninfected food supply is increased, then the probability of the tick larvae's feeding on the uninfected food increases=>number of ticks getting infected is "likey' to decline.
its talking of a possibility.

if the larvae fed only once and that too more likely on uninfected food, then possibly fewer larve would get infected. so C strengthens

why you guys think about B

HI MOHIT

HERE IS THE REASON WHY D IS WRONG:l

D. A single host animal can be the source of bacteria for many tick larvae.

YOUR UNDERSTANDING OF D WOULD BE THAT AS no. of other animals will be increased and according to D as single host anmal can cultivate many tick larve, so increasing no. of other animal would transfer many tick from mice to the other animals

However, the case may be that tick larve can feed many times and on many animals, than in that case same larva can feed on mice at one time and on other animal at othertime.

This contradiction is eliminated only by option C.

siddharth rastogi wrote:HI MOHIT

HERE IS THE REASON WHY D IS WRONG:l

D. A single host animal can be the source of bacteria for many tick larvae.

YOUR UNDERSTANDING OF D WOULD BE THAT AS no. of other animals will be increased and according to D as single host anmal can cultivate many tick larve, so increasing no. of other animal would transfer many tick from mice to the other animals

However, the case may be that tick larve can feed many times and on many animals, than in that case same larva can feed on mice at one time and on other animal at othertime.

This contradiction is eliminated only by option C.

Hi siddharth,

Thanks. Got the same....

I believe the correct answer should be B