Messages are transmitted from your spinal cord to your heart muscles by the
a)sensory nervous system.
b)somatic nervous system.
c)central nervous system.
d)autonomic nervous system

The Correct answer is D

Explanation: The Autonomic Nervous System is that part of Peripheral Nervous System that consists of motor neurons that controls the internal organs. The autonomic system controls muscles in the heart, the smooth muscle in internal organs such as the intestine, bladder, and uterus.

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im not intirely sure but i think the anwser is d relative humidity