One portion of a homeostatic feedback mechanism carries output from the control center to the organ that carries out the response. what is the term for this portion?

efferent pathway

Explanation:

efferent pathway - it is the pathway used by signal to get away from the nervous system. After getting signal from the brain, efferent signal direct body to do according to the received signals.

while on the other side, afferent signals related to the signal that sends by the body to the brain. which is opposite to the efferent signals

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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