how the medical conditions such Asthma, Anemia, Diabetes, and Injury to Pancreas, can prevent cells from not getting enough molecules to function?

Feedback mechanisms regulate the rate of enzyme activity, effectively "turning off' an enzyme in a reversible way until more product is needed. which of the following would be most effective as a feedback mechanism? a. reduced concentration of product b. increased concentration of substrate c. a change in ph d. temporary binding of a non-substrate molecule in the active site