Final answer:
HIV-1 is highly lethal due to the increase of viral loads over time, its short-sighted evolution, its targeting of host immune cells, and its high mutation rate that allows quick adaptation and resistance to host defenses and treatments.
Step-by-step explanation:
Among the options provided, the reasons that may explain why HIV-1 is highly lethal are:
- HIV viral loads increase over time, which can lead to the weakening of the immune system.
- Evolution is short-sighted, meaning that the virus doesn't plan for its long-term survival but instead rapidly adapts to the short-term challenges it faces.
- HIV infects host immune cells, primarily CD4+ T cells, which are crucial for the immune response.
- The high mutation rate of RNA viruses, including HIV, allows natural selection to act rapidly, enabling the virus to evolve resistance to host defenses and treatment efforts.
All of these factors contribute to the virus's lethality and its ability to persist within an infected individual. In addition to these points, HIV's ability to create proviruses and integrate into the host's genome makes it impossible for the immune system to fully eliminate the virus, even with the presence of antiviral treatments.