The result of this union will be a cell with three copies of chromosome 21. Recall again that we've only been considering chromosome 21 so far. Chromosome nondisjunction is generally rare, so the new cell probably has two copies of all of the other 22 chromosomes, just as it should.
When is Mother's Day 2017? Mother's Day 2017 is on Sunday, May 14, 2017 (in 270 days). Mother's Day 2016 has already passed - it was on Sunday, May 8, 2016, 101 days ago.
Mother's Day in 2015 is on Sunday, the 10th of May. In the United States, Mother's Day is celebrated on the second Sunday of May. In some countries it was changed to dates that were significant to the majority religion, or to historical dates.