One of the functions of the endocrine system in the body is to what

Produce and secrete hormones.

Of that are from eating black  foods or iron supplements. the most common condition causing  it is a bleeding ulcer.  black poop caused by blood indicate a problem in the upper digestive tract.     along with pain, vomiting, or diarrhea is cause to see a doctor right go see a doctor

Ijust took the test and the answer is true