#19 - Main Point

[Administrator]

Complete Question Explanation
(See the complete passage discussion here: lsat/viewtopic.php?t=11562)

The correct answer choice is (E)

The answer to this question is prephrased in the VIEWSTAMP analysis above, and restated with greater specificity in correct answer choice (E): A new hypothesis about pathogens is presented, the relationship between virulence and mode of transmission is discussed, and pathogens with long stand-along life spans are presented as among the most dangerous.

Answer choice (A) is inaccurate, because the author does not make the assertion that directly transmitted pathogens are just as virulent in general; those presented at the end appear to be the exception to the general rule relating greater virulence to indirectly transmitted pathogens. Answer choice (B) is inaccurate, because the benign relationship seems to describe many pathogenic relationships—the author does not claim that most pathogens incapacitate or overwhelm. The point raised in incorrect answer choice (C) is accurate, but is mentioned as a side point toward the end of the passage. It is certainly not the author’s main point. Answer choice (D) is inaccurate, because the passage explains that even a dead host does not preclude a pathogen’s evolutionary success.

[mollylynch]

I am still having trouble seeing why answer A is wrong and E is right. Can you explain?

[Jeff Wren]

Hi Molly,

Before looking at Answers A and E, let's examine the key idea in the passage and the three types of pathogens that are discussed in the passage.

The key idea in the passage appears at the beginning of paragraph two. The first sentence in paragraph two states that a pathogen's virulence (basically how severe or deadly it is) is a function of how it is transmitted (its mode of transmission). This is the key concept of the passage. The three different types of pathogens discussed in the rest of the passage illustrate this idea.

The first pathogens described are the "normal" direct contact pathogens like the rhinoviruses that cause the common cold. These pathogens cannot survive outside their hosts for long. Because these require person-to-person transfer, they are less severe (because if a person is very sick lying in bed and/or dying, that person can't spread the pathogens as easily).

The second pathogens described are the vector pathogens that are transmitted by an agent like a mosquito. Since these pathogens don't require person-to-person transfer, they can be and often are much more severe/deadly.

The third pathogens described are the "sit and wait" pathogens. While these pathogens are also directly transmitted, they are the exceptions to the "normal" direct transmission pathogens discussed above because these can survive outside their hosts for weeks or months. Since they can survive for so long outside their hosts, they don't need their hosts to be healthy enough to get around (unlike regular direct transmission pathogens) and these can be very severe/deadly.

The main point of the passage should mention how the virulence of the pathogens is a function of their mode of transmission and then briefly mention the three types of pathogens that show how this works. Answer E does this perfectly and is the correct answer.

Answer A fails to mention the key idea that the virulence of the pathogens is a function of their mode of transmission, and it fails to mention the "normal" direct transmission pathogens that aren't as virulent.