After the triple cores melted during nuclear fusion
when a new cell is made through mitosis a nuclear membrane is formed around the nucleus (center of cell that controls everything).
In mitosis, the nuclear membranes form around the chromosomes at the telophase.
The nuclear membrane reforms around the nucleus during Telophase, the last phase of mitosis.
Telophase
Chemical synthesis form a new molecule; nuclear fusion form a new atom.
Telophase.
New vesicles come from the lipid membranes. In most cases, they will form naturally as a result of their properties.
Both Chemical and nuclear reactions form new substances.
It is Telephase because in Anaphase the centromeres split, and the sister chromatids are pilled to the opposite poles of the cell by the spindle fibers. In Cytokinesis it is already split and it made two identical nuclei.
Only a plant has a cell wall. Animals have cell membranes.
Fission.