Final answer:
Enveloped viruses like the influenza virus and HIV, which have a viral envelope, survive better outside the body. Their structural features and ability to exit the host cell without killing it contribute to their resiliency. Virologists study these characteristics for better disease prevention and treatment through vaccines and antiviral drugs.
Step-by-step explanation:
Viruses that survive better outside the body tend to have certain structural characteristics that provide them with resilience in the external environment. Enveloped viruses, such as the influenza virus and HIV, have a lipid bilayer known as a viral envelope, acquired from the host cell membrane. This envelope allows these viruses to persist outside the host by fusing with the plasma membrane, which permits the virus to exit the host cell without destroying it, thus keeping their propagation cycle ongoing as long as the host cells are alive.
Virus durability in the external environment is also influenced by their size, shape, and genetic composition, with some viruses being inherently more stable and capable of withstanding harsher conditions than others. However, these characteristics alone do not solely determine a virus's ability to persist outside the body; external factors such as temperature, humidity, and ultraviolet radiation also play a critical role.
Overall, virologists engage in the study of these organisms to understand their complexities. Knowledge of how different viruses survive and thrive outside the body is essential in developing therapeutic and preventive measures, including vaccines and antiviral drugs to combat viral diseases.