What is the difference between enzymes, catalysts, and

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms

_tissues respond quickly to outside stimuli a) epithelia b)nervous c)muscular d)muscular and nervous