Its b mark my word trust me
We breath oxygen because it is needed to burn fuel [ sugars and fatty acids] in our cells to produce energy. Oxygen is also brought into the lungs via breathing; where it is transported by red blood cells to the entire body to be used to produce energy. The food we eat gives us protein, sugars, vitamins etc. for energy
Answer:
D, C and A are the correct options.
B is less likely rather is a personal reference.
