Whether it is brand-new or years old, a mattress too soft for your comfort level may make for many restless nights. As long as the mattress is in good shape, there's no need to replace it to achieve the desired level of firmness.Instead, purchase a firm topper, slide a bed board beneath the mattress, or add extra support to the bed frame itself. sheet of plywood cut to the same size as the mattress offers support for a mattress that has lost some of its firmness. Slide the plywood between the mattress and box spring.
Human cells normally contain 23 pairs of chromosomes, for a total of 46 chromosomes in each cell (illustration). A change in the number of chromosomes can cause problems with growth, development, and function of the bodyâs systems.
Down Syndrome History. By Dr Ananya Mandal, MD. Down syndrome or Downâs syndrome is a congenital condition caused by the presence of an additional copy of chromosome 21 in a personâs cells. This is also referred to as trisomy 21. Humans usually have 46 chromosomes in every cell, with 23 inherited from each parent. Due to the extra copy of chromosome 21, people with Downâs syndrome have 47 chromosomes in their cells.