Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

Answer:
((2 (cm squared)) + (4 (cm squared))) / 2 =
0.0003 m2
Explanation:
Answer:
formed of ice, rock, and dust
develop tails near the Sun
Explanation:
Comet is a smaller celestial body which is mainly composed of ice and dust.
The other components of this comet are rocks and gas.
When any comet approaches a sun it can deliver a tail of dust or gas.
hope this will help you