Biotic factors are the living things in the ecosystem, such as plants, animals, fungi, bacteria.. The importance of the biotic factors is that they create changes in the cosystem. They affect each other and influence the health of the ecosystem, because a healthy ecosystem has a balance of biotic examples.
Abiotic factors are all of the non-living things in an ecosystem, such as water and air. Abiotic factors are especially important because they directly affect how organisms survive.
Gas exchange occurs at the alveoli in the lungs and takes place by diffusion. The alveoli are surrounded by capillaries so oxygen and carbon dioxide diffuse between the air in the alveoli and the blood in the capillaries.
