The homeostatic mechanism, in which a stimulus changes the regulated variable in one direction but the response changes the variable in the opposite direction, is called a:

Negative feedback mechanism

Explanation:

The negative feedback mechanism refers to the mechanism that restores the homeostasis by counteracting the deviation.  

Here, the change in the controlled conditions is reversed by producing a response and the response reverses the stimulus.  

For example, increased blood sugar levels stimulate the release of insulin from the pancreas to restore normal blood sugar levels. Insulin makes the cells to absorb glucose from the blood to lower down the blood glucose level.  

As the normal blood glucose levels are restored, insulin secretion is lowered down or stopped.  

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