Answer: feed-back
When the product of a metabolic pathway accumulates, it may be able to slow down or turn off the pathway by inhibiting the activity of an enzyme that catalyzes an early step in the pathway. This is referred to as feed-back inhibition.
Explanation:
Feed-back inhibition is said to occur when the final product of a biochemical pathway signal the inactivation of the starting materials of the pathway.
For example: when pyruvate signal the inactivation of phosphofructokinase, the glycolytic pathway gets turned off.
I think the answer would be 1,or 2
