Its B clearing and farming. Because if you think of it when someone clears trees and bushes they most likely won't come back.
This would mean a change in base sequence, which is very important for the proteins to carry out their function. It could lead to a mutation and a change in the role of the protein.
Skeletal mass increases dramatically during childhood and adolescence, and decreases dramatically at the beginning of the fourth decade of life and decreases with age, with an exception of the skull.
Hope this helps! Have a BLESSED day! :-)
The Major function of the respiratory system is to exchange oxygen and carbon dioxide. Inhaled oxygen enters the lungs and reaches the alveoli, the layers of the cells lining the alveoli and the surrounding capillaries are each only one cell thick and are in very close contact with each other, the barrier between air and blood averages about 1 micron in thickness. Oxygen diffuses quickly through the air-blood barrier into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled.