Diseases can spread rapidly in cities. If a disease kills many people in a city but fewer in a rural area, this is an example of -Density independent factor
-Exponential population growth
-Density dependent dependent factors
- logistical population growth.

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange