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.
Egg, larva, pupa and adult
Do you mean:
In a typical cell membrane, *phospholipids* arrange themselves to form a ?
In that case, the answer is:
Bilayer