B. 245 million
from the end of Carboniferous Period to the beginning of the Triassic period
The answer is B I believe!
There are 3 major parts of the respiratory system: the airway, the lungs, and the muscles of respiration. The airway, which includes the nose, mouth, pharynx, larynx, trachea, bronchi, and bronchioles, carries air between the lungs and the body's exterior.
