I want to know the answer to the following question:
What results from the development of xylem on the inside and phloem on the outside?
All the background I'm provided with is that "Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings.". Is that enough to answer the question?
Answer: no