The heartbeats of the heart are controlled by the sinoatrial node also known as the pacemaker of the heart. The impulse is generated in the conducting cells of the pacemaker as a result of the movement of sodium, potassium and calcium ions.
The sodium channels allow the movement of sodium into the cell which depolarizes the membrane from -60mv to -40 mv. At this point, the calcium gated channels open which allow the entry of the calcium in the cell which depolarizes the cell up to +5mv.
At this point, the potassium channels open which allows the potassium ions to move out of the cell. This repolarizes the cell and hence the cycle again begins. Reducing the permeability of the potassium ions help generate the autorhythmicity due to repolarization and thus is the correct answer.
The two world wars chaos many writers, visual artists and musicians to deeply present their tragic experiences in this horrible times. These were the times where people were scared or questioned the days they have left and survival was at the top of the chart. One example of an art expression is
(TT) Is fully tall. (TS) Is medium. So it can be assumed that (SS) is short. When forming a cross, you cross TT and TS to generate a phenotypic ratio of 1x1 or a genotypic ratio of 1 TT, 1 TS. Making it exactly split in half in 50/100.