Basically let's you breathe easier.
Explanation:
The alveoli are only one cell thick. Which allows relatively easy passage of oxygen and Carbon Dioxide between the alveoli and blood vessels. (Capillaries
Answer: I think it is true! Sorry of it is wrong :)
Answer:
Be honest Greenhouse gases.
the mass of the system must remain constant over time
In other words matters cannot be created or destroyed, the overall amount will remain the same
