1. The cell in this demonstration began mitosis with two chromosomes. How many chromosomes did it have at the end of mitosis? 2. Why must a cell make a copy of tis chromosomes before cell division?

3. What structure holds sister chromatids together?

Once mitosis is complete, the cell has two groups of 46 chromosomes, each enclosed with its nuclear membrane. The cell then splits in two by a process called cytokinesis, creating two clones of the original cell, each with 46 monovalent chromosomes.When one cell divides into two, both must have a copy of the genetic information. Therefore, before cell division occurs, the genes must also make duplicates of themselves so that all the important genetic information ends up in each of the new cells.Centromeres.… that hold together the two chromatids (the daughter strands of a replicated chromosome). The centromere is the point of attachment of the kinetochore, a structure to which the microtubules of the mitotic spindle become anchored.

The mass has escaped into a gas which you can not see so the law stays true.

It was ernest rutherford