Major disease affect the population because they kill large numbers of people.

Epidemic? The Black Death or Bubonic Plague might be what you're looking for .

Major disease "Pandemics" affect the population because they kill large numbers of people.

Pandemics is your answer

“larger states wanted congressional representation based on population, while smaller states wanted equal representation. they met in the middle. larger states wanted congressional representation based on population, while smaller states wanted equal representation.” i hope this information you.