Final answer:
At the end of each pandemic, if a virus could only live in humans, the virus would likely face a decline in transmission and eventually die out.
Step-by-step explanation:
At the end of each pandemic, if a virus could only live in humans, the virus would likely face a decline in transmission and eventually die out. This is because as the pandemic progresses, more and more individuals would acquire immunity to the virus either through natural infection or vaccination. With a large enough proportion of the population immune, the virus would have fewer opportunities to spread from person to person and its transmission chain would be broken. Over time, the virus would have difficulty finding new susceptible individuals to infect, leading to its eradication.