Your friend says the following to you: "The lungs are the main part of the respiratory system. You really don't need the rest of the other organs [in the respiratory system]." Prove this to be a false statement.

This statement is false because the respiratory system includes  muscles that power your lungs. These muscles work together to move oxygen through your body and it cleans out waste like carbon dioxide.

The respiratory system also allows us to speak and smell. So we clearly need all of the organs in our respiratory system.

his research revealed two genetically different groups of prokaryotes, which justified splitting kingdom monera into two kingdoms. the genetic and cellular differences were so great, that these two kingdoms were eventually placed into different domains in the current three-domain system.