Write a essay answering these following questions.

Pandemics have occurred all throughout history. Why do pandemic occur? Can we better prevent the spread of disease by lifestyle changes? Discuss some pandemics that occurred previous to COVID-19. Where did the pandemic start? How far did it spread? How long was the pandemic? What was the cause? What was the death toll? Were there environmental factors that contributed to the spread of the disease? What were the symptoms of the disease? Could the spread of the disease been prevented? What were some of the symptoms of the disease?