Stem in plants:
Is the movement of material like water and minerals from roots to leaves. And they storage foods.
You need more context for people to answer the question. We can’t respond with so little. We need to see the sentence so we can answer you problem.
The Conclusion, because in the conclusion you are wrapping up all of your thoughts and PROVING YOUR POINT.
B or D I am not sure yet but I think it is B or D.