Answer - An increase in the width of Stem
(Was answered before in the community)
Credit goes to [PeachSoda]
Reasoning Why I agreed - Plants can grow in the root tips which shows the progression of growth and thats why you would find a lot more plant cells because it will always keep growing.
The inner planets are those that orbit closer to the sun: mercury, venus, earth and mars.
Attending to the size this is the increasing order: mercury, mars, venus and earth.
Earth is the largest of the inner plantes.
D. sum of all chemical reactions in an organism