What is the purpose of the little hairs inside the nose?
To fight disease.
They serve no purpose.
To keep dust out of the lungs.
To tickle the nose and cause sneezes.
1. Taking in of O2 and giving out of CO2 2. Diffusion of O2 into blood and CO2 out of blood.3. Transport of oxygen to the cells.4. Combination of glucose inside cells to release energy.
Oxygen moves from the lungs into the bloodstream through:
nerve fibres
a large artery in the heart
small blood vessels in the lungs
a tube in the lungs called the jugular vein
What is the percentage of CO2 in the air we breathe out?
0.03%
4%
6%
2%
