<span>Amino acids are the components of proteins, and proteins are one of the main food groups that human require in order to be fit, healthy and strong. There are twenty different naturally occurring amino acids, each one abbreviated to a three letter code, or often just one letter, for example, the amino acid Alanine is abbreviated "Ala", or just "A".
There are nine amino acids that the human body cannot make for itself, and therefore must be obtained from the diet, i.e protein rich foods such as milk, cheese, and lean meats such as beef, and chicken. These nine amino acids are as follows, Leucine (L), Methionine (M), Phenylalanine (F), Valine (V), Threonine (T), Tryptophan (W), ,Isoleucine (I), Lysine (K), and Histidine (H).
If these amino acids cannot be obtained then various developmental problems arise such as having poor muscle mass, fragile hair, poor skin complexion, and quality, and more seriously, problems such as exhaustion/fatigue and dizziness.</span>
C. A 50% oxygen saturation level of blood returning to the lungs might indicate an activity level higher than normal.
