Answer:
<em>D</em>
Explanation:
<u>all of the above</u>
<u>they're all helpful.</u>
<span>There are many ways our body sends messages in order to help regulate bodily function, like mood, body heat, and so forth. One way our body communicates is through the endocrine system. This sends chemical messengers in the form of molecules like the ones in the picture through our bloodstream to perform specific functions.</span>
