I believe it would be (B) but i’m sorry if i am wrong.
It's usually d,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
I have no clue, there is nothing else here to support your question.
Answer:
well the 1 or 3 is my guess
Explanation:
The 1 is my main answer but 3 is a possibilty i suppose
That would be the Endocrine system which secretes hormones into the blood through glands