Please answer this: I read this background article the other day: As time passes, the number of HIV copies keeps increasing, while the number of helper T cells keeps decreasing. The graph in Figure below shows how the number of T cells typically declines over a period of many years following the initial HIV infection. As the number of T cells decreases, so does the ability of the immune system to defend the body. As a result, an HIV-infected person develops frequent infections. Medicines can slow down the virus but not get rid of it, so there is no cure at present for HIV infections or AIDS. There also is no vaccine to immunize people against HIV infection, but scientists are working to develop one.  I am facing a new situation today: Robert and Justin are both patients in the hospital who are suffering complications from their HIV infections. The doctor is trying to get information from both men about their diseases so he can create customized treatment plans for both men. After a few questions, the doctor discovers that Robert has been infected with HIV for many years, while Justin's infection is quite recent.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Who will have a less weakened immune system?
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Answer: Justin


Please answer this: I read this background article the other day: In slippery conditions some riders prefer to ride fixed because they believe the transmission provides increased feedback on back tire grip. However, there is also an increased risk of loss of control in such conditions. This is especially so when taking into account the large number of riders who ride brakeless. These riders must brake entirely through the drivetrain. Ideally this is done by resisting the forward motion of the pedals, shedding speed while the bike is still moving. Alternatively, though far less efficiently, one can brake by stopping the motion of the pedals in mid-rotation, causing the rear wheel to lock in place, allowing the bicycle to skid and slow down from kinetic friction (see below).[22]  Descending any significant gradient is more difficult as the rider must spin the cranks at high speed (sometimes at 170 rpm or more), or use the brakes to slow down. Some consider that the enforced fast spin when descending increases suppleness or flexibility, which is said to improve pedalling performance on any type of bicycle; however the performance boost is negligible compared to the benefits of riding a free wheel.[23]  I am facing a new situation today: Two villages are inhabited by lots of people that ride bicycles. Hill village is located on a mountain and gets lots of rain, and Low village is situated in a valley, and has more sunny days.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which village has more cyclists going downhill?
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Answer: Hill


Please answer this: I read this background article the other day: Increased solar ultraviolet radiation resulting from the Antarctic ozone hole has reduced marine primary productivity (phytoplankton) by as much as 15% and has started damaging the DNA of some fish. Illegal, unreported, and unregulated fishing, especially the landing of an estimated five to six times more Patagonian toothfish than the regulated fishery, likely affects the sustainability of the stock. Long-line fishing for toothfish causes a high incidence of seabird mortality.  I am facing a new situation today: Bob was studying about Earth's atmosphere. He found that increased depletion of Earth's ozone layer is a relatively new phenomenon. Most scientists would blame the CFC gases for the depletion of ozone layer. In the early twentieth century ozone layer was relatively stable. Bob labeled that time as time A. But in the late twentieth century situation changed with seasonal depletion of ozone layer. He labeled that time as time B.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which time would see more phytoplankton, time A or time B?
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Answer:
time A