Final answer:
The primary reasons why some individuals survived the Black Death while others did not mainly revolve around immune and genetic factors determining their ability to fight off the infection caused by Yersinia pestis.
Step-by-step explanation:
The question is why some people died from the Black Death while others did not. Research indicates that immunity and genetic factors played a significant role in determining an individual's fate during the Black Death. Heterogeneity in the immune system's ability to mount an appropriate response against the Yersinia pestis pathogen could explain differential mortality. Various historical and biological sources suggest that apart from being in poor health due to factors such as malnutrition or prior disease, individuals's immune responses were crucial in surviving the plague, emphasizing the impact of biological factors on plague mortality.
It is also important to note that while religious beliefs and personal hygiene might have influenced social behavior, these did not directly cause or prevent plague mortality. The pathogen spread through fleas and rodents, as well as human-to-human contact, so exposure and immune response were key factors rather than clothing or piety. Overall, the ability to survive the Black Death was multifactorial, with immune system strength and overall health being primary determinants.