SAQ help please: passage: "The Spanish flu was one of the deadliest natural disasters in history—a potent reminder of the threat posed by disease.

Humanity seems to need such reminders often. In 1948, shortly after the first flu vaccine was created and penicillin became the first mass-produced antibiotic, U. S. Secretary of State George Marshall reportedly claimed that the conquest of infectious disease was imminent. In 1962, after the second polio vaccine was formulated, the Nobel Prize–winning virologist Sir Frank Macfarlane Burnet asserted, ‘To write about infectious diseases is almost to write of something that has passed into history.’

Hindsight has not been kind to these proclamations. Despite advances in antibiotics and vaccines, and the successful eradication of smallpox, Homo-sapiens is still locked in the same epic battle with viruses and other pathogens that we’ve been fighting since the beginning of our history. When cities first arose, diseases laid them low, a process repeated over and over for millennia. When Europeans colonized the Americas, smallpox followed. When soldiers fought in the first global war, influenza hitched a ride, and found new opportunities in the unprecedented scale of the conflict.”

"The Next Plague Is Coming. Is America Ready?” by Ed Yong, the Atlantic, 2019

a) Identify ONE environmental factor, alluded to by the author, that is typically present and required for the spread of infectious disease on an epidemic or pandemic scale.

b) Identify ONE specific example of a 20th-century health epidemic that encouraged technological advancement and that is NOT explicitly referenced by the author.

c) Explain ONE specific example of why the optimism of Sir Frank Macfarlane Burnet and George Marshall may have been misplaced.