If the inner lining of the air sacs neither thin nor highly vascularized, then it can be inferred that AIR SACS ARE CANNOT BE THE SITES OF GASEOUS EXCHANGE BETWEEN AIR AND BLOOD. Air sacs are generally lined with mucus and surrounded with blood capillaries.
In case of birds, air sacs play an important role in respiratory system.
A desert is a hot wasteland covered with sand and a tundra is a frozen wasteland covered in ice
Living organisms also contain a lot of hydrogen, oxygen, nitrogen, sulfur, and phosphorous. Those atoms combine together to form complex molecules of various types: proteins, carbohydrates, lipids, and nucleic acids.
The difference is that emphysema and chronic bronchitis are different types of chronic obstructive pulmonary disease (COPD). <span />
Answer:
Sand
Explanation:
Space, water, energy, and air are all needed for an organism to survive. Sand is just somewhere an organism could accustom to live in that environment.
