A higher rate of concordance in monozygotic twins in comparison to dizygotic twins is a proved evidence of the contribution of the genetic constituent as monozygotic twins are genetically more identical in comparison to dizygotic twins. The monozygotic twins share all the genes in common and dizygotic twins on average share half of their genes in common.
Thus, the concordance in monozygotic twins is more in comparison with that of dizygotic twins, which shows the contribution of genetics to this trait.
Each time your heart beats, an electrical signal travels through the heart. An EKG can show if your heart is beating at a normal rate and strength. It also helps show the size and position of your heart's chambers. An abnormal EKG can be a sign of heart disease or damage.
Atria is a large part of the heart so too big for cells; arteries & veins lead away or to the heart. Capillaries are the smallest vascular structures that allow materials to be exchanged easily between cells.
