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.
Medical Genetics: Types of Genetic Changes. The human body has 20,000 to 25,000 different genes. Genes are located on chromosomes, which are stick-shaped structures in the middle of each cell in the body. Each cell usually has 46 chromosomes grouped in 23 pairs. Each gene has a specific function. And when a gene or chromosome is abnormal, it may cause health problems in the body.