The lactose (lac) operon in E. coli is an example of a repressed gene when lactose is not available in a cell . In 3-5 sentences, explain what this means using correct terminology please make the answer short

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?