After the Russian Revolution of 1917, Georgia declared independence in 1918, but the democratic Republic of Georgia, ruled by a social-democratic government, was invaded by the Red Army in 1921, a few days after it was recognized by European states.
And.. The Semilunar Valves prevent the back flow of the blood from the arteries to the ventricles. Explain what happens to tissues, such as the heart, or the brain, if oxygenated blood is not delivered in a timely manner. The tissue of the organ starts to die.
Some highly active organs, such as your brain and heart, can be irreversibly damaged if their oxygen supply is interrupted for only a few minutes. Most of your cells, tissues, and organs lie far beneath the surface of your body and don't have access to the oxygen in the atmosphere.