The picture represents a structure of the respiratory system. Alveoli in the lungs.

Which is the function of this structure?

to bring air into the body

to exchange oxygen with carbon dioxide

to carry air to the lungs

to release oxygen from the body

Cells destroy body cells infected by a virus or bacteria. killer t t memory t none of the above

Which of these has happened to your food by the time it reaches your small intestine? a. all the macromolecules have been broken down completely. b. lipids and starches have been partially broken down. c. starches and proteins have been partially broken down. d. proteins and lipids have been broken down into subunits.

What causes eclipses? check all that apply. earth's rotation on its axis moon's shadow covering the sun earth's shadow covering the moon earth's orbit and moon's orbit occasionally aligning the moon and sun's gravity pulling in the same direction