How does the respiratory system aid the digestive system a. the lungs take in oxygen to aid in food digestion

b. the lungs take in carbon dioxide to aid in food digestion

c. the expand the diaphragm, which helps to push the stomach during digestion

d. the lungs contract the diaphragm, which helps to push the stomach during digestion

PLEASE HELP ASAP ! :)

Astable electron arrangement for an atom is one that does not easily change. how is this arrangement arrived at? a. valence electrons are transferred or shared to create a full outer shell of electrons. b. valence electrons are discarded into space to create a full outer shell of electrons. c. protons (positive charge) pair with valence electrons (negative charge) to create a strong bond. d. outer shells with valence electrons are transferred or shared.