Behavioral physiologist is studying the homeostatic control of blood pH. In a trial, a lizard runs on a treadmill for a set amount of time and the blood pH is measured. The blood pH drops as carbon dioxide is released into the bloodstream. The body uses peripheral chemoreceptors to regularly measure blood pH. These chemoreceptors are the in this example.

sensor

Explanation:

Homeostasis refers to the ability of an organism to maintain the internal conditions of the body irrespective of the external conditions.

The homeostasis is maintained by the homeostatic mechanism which involves the 3 components which are the receptor or sensor, the integrating centre and the effector or organ.

In the given question, the peripheral chemoreceptors measures and sense the pH of the blood therefore the peripheral chemoreceptor will be considered as the "sensor component" of the homeostatic mechanism.

Thus, the sensor is the correct answer.

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