1. Ground tissue is found in a plant's roots, stems, and leaves. The answer to your question is D.
2. If some of the xylems of a young oak tree were destroyed, it would most likely interfere with the tree’s ability to conduct water to the leaves. The answer to your question is D.
3. Meristems are an area of unspecialized cells in which mitosis produces new cells that are ready for differentiation. The answer to your question is B.
I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.