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.
Often, heart defects and other problems are present. It is one of the most common genetic birth defects, affecting approximately 1 in 800 babies. Chromosomes are the structures in cells that contain the genes. Down syndrome is caused by extra genetic material from chromosome 21. Affected persons have two normal copies of number 21 chromosomes, plus extra chromosome number 21 material attached to another chromosome. For that reason, Down syndrome is sometimes referred to as Trisomy 21.