The rule is, once a rollover is completed and a 72(t) is setup to pay out an income stream, it must continue until the age of 59 Â½ has been reached or for a minimum of 5 years, whichever comes last. For example, if you start a 72(t) at the age of 57, it must run until you are age 62, then it stops.
Then, at a critical point during interphase (called the S phase), the cell duplicates its chromosomes and ensures its systems are ready for cell division. If all conditions are ideal, the cell is now ready to move into the first phase of mitosis.
The answer is 20. Duplicated chromosome has two sister chromatids, identical copies of the chromosome. These two chromatids are joined at the region called centromere. Therefore, one duplicated chromosome has one centromere and two sister chromatids. If there are 20 duplicated chromosomes in a cell, there will be 20 centromeres.