I would go with D, speaker. A poem is written by an author, but the author isn't always the speaker.
Hypothalamus. Just answered the question a couple mins ago :)
Answer:
Cell membrane
Explanation:
It encapsulates and delimits the cell. It controls what goes into the cell and what goes out of it. It holds the cell organelles together. It maintains a homeostasis state.
I am thinking D. But I am not sure that it is the answer.
Where a lot of vegetation is current
