ajaym28 wrote:
The body of anyone infected by virus X will, after a week, produce antibodies to fight the virus; the antibodies will increase in number for the next year or so. There is now a test that reliably indicates how many antibodies are present in a person's body. If positive, this test can be used during the first year of infection to estimate to within a month how long that person has had the virus.
Which one of the following conclusions is best supported by the statements above?
(A) Antibodies increase in number only until they have defeated the virus.
(B) Without the test for antibodies, there is no way of establishing whether a person has virus X.
(C) Antibodies are produced only for viral infections that cannot be fought by any other body defenses.
(D) If a person remains infected by virus X indefinitely, there is no limit to the number of antibodies that can be present in the person's body.
(E) Anyone infected by virus X will for a time fail to exhibit infection if tested by the antibody test.
In anyone, antibodies will be produced after a week.
Antibodies will increase in number for the next year or so (after that, we don't know)
There is now a test that reliably indicates how many antibodies are present in a person's body.
If positive, this test can be used during the first year of infection to estimate to within a month how long that person has had the virus.
Which of the following is true?
(A) Antibodies increase in number only until they have defeated the virus.
We don't know. We just know that for a year, they keep increasing in number.
(B) Without the test for antibodies, there is no way of establishing whether a person has virus X.
The argument doesn't tell us anything about this. There may be other ways too.
(C) Antibodies are produced only for viral infections that cannot be fought by any other body defenses.
Again, not known. Perhaps other defences get involved too. We don't know the conditions under which antibodies are produced.
(D) If a person remains infected by virus X indefinitely, there is no limit to the number of antibodies that can be present in the person's body.
Can't say. Though, the argument does tell us that the number of antibodies increase for a year. Perhaps, after that the number doesn't increase.
(E) Anyone infected by virus X will for a time fail to exhibit infection if tested by the antibody test.
Correct. The antibodies are produced after a week. So for a week, the person will fail to exhibit infection if tested by antibody test (some other test may still show infection)
Answer (E)