PLEASE HELP ME EMERGENCY PLEASE HELP Which of the below best describes the function of the respiratory system?

To circulate nutrients and gases throughout the body.

To bring oxygen into the body and to remove carbon dioxide from the body.

To break down food to glucose molecules that the cells can use.

(This is 7th grade science)

How does the fermentation of pyruvic acid in cells contribute to the formation of atp? a. it completes the oxidation of glucose to co2, creating atp. b. it generates lactic acid, which cycles back through the krebs cycle, producing 2 atp molecules. c. it converts fadh2 to phosphate, which bonds with adp. d. it produces 2 nad+ molecules, which cycle back to fuel the glycolysis reaction, allowing 2 atp molecules to be produced.