a.
When you used your muscles too much you feel
Relax
b. comfortable
c. tired
Carbon dioxide leaves in our body through
a.
Inhalation
b. exhalation
When air goes to the air sacs oxygen goes to the
a.
wall of the air sacs b. wall of the lur
d. walls of the heart
Why do we need oxygen? All your answers are corre
a. To stay alive b. to have energy
Vhat is the major organ in the respiratory system?
b. lungs
Heart
c. kidneys
a.​