Amino acids are considered as the building blocks of proteins.
Proteins in the body consist of 20 different amino acids, some of which can be synthesized by the body itself.
Each unique protein is formed by the combination of these proteins in several ratios and sequences.
Glycolysis is the first stage of cellular respiration that occurs in the cytoplasm of animal cells. It is the only stage that occurs outside of the mitochondrion.
I think the correct answer from the choices listed above is option A. It is the alveoli that is composed of single layer <span>surrounded by a network of capillaries. These are used to allow oxygen and carbon dioxide to move from the lungs to the bloodstream.</span>