What begins the process of the solar system

Explanation:

Solar system is the collection of eight planets including Sun, Mars, Venus, Earth, jupiter, Mercury, Uranus and Neptune. They all are revolving around the elliptical orbit.  Solar system was formed when cloud of gas and dust was distributed in space. Solar system involves some steps like Nebula collapsing, rotating protostellar disk, center of nebula fusion begins, star is born and planets form.  

Solar system was about 4.6 billion years old. It forms by gravity in molecule cloud.  

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.