The functions of the respiratory system are select all that apply answer choices to pump to the body to deliver oxygen to the body, to remove carbon dioxide from the body, to absorb nutrients

The functions of the respiratory system are:

1) To pump oxygen into the body to deliver it to the cells.
2) To remove carbon dioxide from the body, which is a waste product of cellular metabolism.
3) To help regulate the pH levels of the body by controlling the levels of carbon dioxide and oxygen.
4) To filter and humidify the air we breathe.
5) To produce sound for speech and other forms of communication.
6) To assist with the sense of smell through the olfactory system.

Therefore, the correct answer choices are:
- To pump oxygen to the body to deliver it to the cells.
- To remove carbon dioxide from the body.