Thank you for the opportunity to help you with your question!
>External respiration involves transfer of gas from between the lungs and the outer environment , while internal respiration involves transfer of gas between the blood and the cells .
> External respiration involves inhaling in oxygen and exhaling Carbon dioxide , while internal respiration would involve metabolic process where oxygen is released to the to the cells and carbon dioxide is absorbed in the blood.
2..Mouth breathing changes the face appearance
. It causes frequents headaches
. Cause gum disease
. Causes sore throats and cold symptoms
. Bad breath
. Digestive disturbance
3 They purify ,humidify and warm the incoming air .
4. physical factors - talking breathing and exercise can regulate the rate and depth
Chemical factors - Increased level of carbon dioxide and oxygen