Question

HIV-1 is highly lethal in humans because:

1) The immune response against HIV creates more of the cells that are hosts to HIV virions
2) The evolutionary history of HIV and of primates has resulted in unique molecular properties in both organisms that enable HIV to be particularly infective and damaging
3) The high mutation rate of RNA viruses allows natural selection to act rapidly, enabling the virus to evolve resistance to host defenses
4) Natural selection favors high infectivity of the virus, which is linked to high viral loads
5) All of the above

Answer 1

HIV-1 is highly lethal due to the increase of host cells for the virus, unique molecular properties stemming from a shared evolutionary history with primates, rapid viral mutation leading to resistance against host defenses and drugs, and natural selection encouraging high infectivity.

Step-by-step explanation:

HIV-1 is highly lethal in humans for several reasons:

1. The immune response against HIV inadvertently creates more of the cells that are hosts to HIV virions, which the virus then infects and destroys.
2. The unique molecular properties due to the evolutionary history of HIV and primates make HIV particularly infective and damaging.
3. HIV's high mutation rate allows rapid natural selection, enabling the virus to evolve resistance to host defenses and antiviral drugs.
4. Natural selection favors high infectivity of the virus, which leads to high viral loads and increased spread of the virus.

All of these factors contribute to the lethality of HIV-1 in humans.