During DNA replication a pair of chromosomes of from one cell genders two duplicated chromosomes (so the number of chromosomes is duplicated), then in the mitosis process the cell split into two identical cells each with half of the duplicated chromosomes, so at the end one cell with two chromosomes form two cells each with two chromosomes. So, the new generation of cells has the same number of chromosomes.
The surface area of a sphere can be approximated as follows: Surface area = 4πr2; where r is the radius of the sphere; π is a constant that is roughly equal to 3.
